From hbaruch at bgu.ac.il Tue Jan 2 11:07:45 2007 From: hbaruch at bgu.ac.il (hbaruch@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-02 Condensed Matter Seminar- Special Message-ID: <200701020907.LAA9204458@tzin.bgu.ac.il> Condensed Matter Seminar- Special DATE: 02-01-2007 TIME: 11:15am Tuseday -- note special time! PLACE: Physics club (Building 29, room 002) TITLE: Attosecond coherent control in high harmonic generation SPEAKER: Dr. Oren Cohen, JILA and Department of Physics, University of Colorado at Boulder, USA ABSTRACT/COMMENTS: The conversion of laser light to coherent soft x-ray radiation through high-order harmonic generation (HHG) is the best example of a complex process where attosecond time-scale dynamics can be coherently manipulated, thus representing the fastest technology devised by mankind. In HHG, an electron is first ionized by the driving laser, then, the electron oscillates in the continuum in response to the laser field, and finally recombines with the parent ion, liberating its excess energy as a very high energy photon. In this talk, I will show that the quantum trajectories of the re-colliding electrons, and therefore the entire HHG process, can be manipulated by an extremely weak laser beam that propagate in the opposite direction to the intense laser pulse that drives the HHG process. Applications of this counter-propagating scheme include (1) selecting which of the electronic quantum trajectories contribute to the HHG process (an important feature for generating atto-second puls es), (2) in-situ probing of the coherent buildup of the harmonic waves, and (3) selectively correcting the large phase mismatch between the driving laser and a high-order harmonic, hence, significantly increasing the conversion efficiency. Potential applications with this unique source, such as ultrafast spectroscopy of materials, imaging of nano structures, and bio-imaging of living cells will be discussed From nano at bgu.ac.il Thu Jan 4 22:40:39 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-03 nanotechnology workshop-CANCELLED Message-ID: <009c01c73040$98a48ef0$1b0e4884@estinano> The Nanotechnology workshop, for Wednesday January 03 is cancelled. ----- Original Message ----- From: Nano To: nano Sent: Friday, December 29, 2006 12:02 AM Subject: 2007-03-01 nanotechnology workshop Nanotechnology workshop, Wednesday January 03, 12:00 building 29, room 306,Chemistry Department seminar room Title : Recent Progress in Accessing the Nanostructure of Liquid Systems by Cryo-TEM Speaker: Prof. Ishi Talmon Department of Chemical Engineering Technion Abstract: Cryo-TEM has become an indispensable tool to acquire high-resolution direct images of self-aggregating nanostrucutred liquids. The methodology that has been developed over the years allows us to capture the nanostructure in its native state of fixed concentration and temperature. A wide range of systems of low- and high-molecular weight solutes, synthetic and biological, has been studied already by the technique. While most cryo-TEM work has been done on aqueous systems, more recently the technique has been extended to non-aqueous solvents as well. The term ?cryo-TEM? actually refers to two techniques: direct-imaging cryo-TEM, by which a thin vitrified sample is examined by the TEM at cryogenic temperatures, and ?freeze-fracture-replication? cryo-TEM (FFR), by which a carbon-metal replica of the fractured fast-cooled specimen is examined at room temperature by the TEM. The two techniques are complementary, as I will explain in my talk. The presentation will begin with a brief description of the two techniques with emphasis on FFR, a most useful technique that is, unfortunately, quite rarely used nowadays. This will be followed by a discussion of the application of cryo-TEM to non-aqueous systems, pointing out the potential and the difficulties of this type of application. The application cryo-TEM to the study of the mechanism of mesophase formation will be described in the final part of the talk. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070104/daba8068/attachment.htm From nano at bgu.ac.il Thu Jan 4 22:48:29 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-10 nanotechnology workshop Message-ID: <00b801c73041$b1617470$1b0e4884@estinano> Nanotechnology workshop, Wednesday January 10, 12:00 building 29, room 306,Chemistry Department seminar room Title : Dynamics and thermodynamics of systems with long-range interactions Speaker: Prof. David Mukamel Department of Physics Weizmann Abstract: Systems with long range interactions (namely with interaction potentials which decay slower than $1/r^d$ at large distances $r$ in dimension $d$) are non-additive. As a result they display unusual thermodynamic and dynamical properties. Some general features of these systems are explicitly demonstrated. In these systems the various statistical mechanical ensembles are not equivalent. It is shown that whenever a model exhibits a first order transition within the canonical ensemble, the corresponding microcanonical phase diagram may differ from the canonical one. These systems are also found to exhibit unusual dynamical properties. Long range interactions may result in breaking of ergodicity, making the maximal entropy state inaccessible from some regions of phase space. In addition in many cases long range interactions result in slow relaxation processes, with time scales which diverge in the thermodynamic limit. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070104/14610522/attachment.htm From physics at bgu.ac.il Thu Jan 4 08:38:54 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-07 special seminar Message-ID: <200701040638.IAA10753865@tzin.bgu.ac.il> special seminar DATE: 07-01-2007 TIME: 11:00 PLACE: Physics club (Building 29, room 002) TITLE: Efficiency, selectivity and robustness of the transport into and out of the cell nucleus SPEAKER: Anton Zilman , Rockefeller University ABSTRACT/COMMENTS: Functioning of eukaryotic cells depends on precise regulation of the transport of proteins in and out of the nucleus. All the transport in an out of the nucleus proceeds through the nuclear pore complex (NPC). NPC is an e±cient transport device, which transports proteins between the nucleus and the cytoplasm in milliseconds time. NPC is highly selective, only allowing efficient passage of the molecules bound to the transporter proteins. Although, one GTP is used per transported cargo, the process of translocation through the pore is passive and does not involve active energy consumption. The key component in the NPC function is the attractive interaction between the transporter proteins, and the flexible filaments, lining the internal surface of the pore. Strikingly, the transport is robust with respect to the delection of up to the half of these flexible filaments. We model the transport through the NPC as diffusion in an effective potential due to attachments to the flexible filaments. Using analytical theory and computer simulations, we explain known functional features of the NPC, in terms of its basic physical properties. Finally, our theory suggests a way for creation of artificial nano-sorting devices. From hbaruch at bgu.ac.il Thu Jan 4 18:04:43 2007 From: hbaruch at bgu.ac.il (hbaruch@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-08 Condensed Matter Seminar Message-ID: <200701041604.SAA11091121@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 08-01-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Square-to-rhomb phase transition in vortex lattices of d-wave superconductors SPEAKER: Prof. Boris Shapiro, Department of Physics, Institute of Superconductivity, Bar-Ilan University ABSTRACT/COMMENTS: A theory of structural phase transition of the vortex lattice in tetragonal superconductors is constructed. The self consistent harmonic approximation for lattice anharmonicities, within the fourfold - symmetric generalization of the nonlocal London model, is used. Thermal fluctuations on the mesoscopic scale are strong enough in this quasi two dimensional situation to affect the location of the square to rhomb transition line in the T-H plane. We find that the slope of the transition line under thermal fluctuations is generally negative: thermal fluctuations favour the more symmetric square lattice. The quenched disorder influences the location of the square-to-rhomb structural transition line. We calculated the transition line in the presence of pinning and find that the disorder, which plays an important role in low T_{c} materials, makes the slope positive, as has been observed in recent experiments. From physics at bgu.ac.il Sun Jan 7 11:34:30 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-10 Organic/Biophysics Chemistry Seminar Message-ID: <200701070934.LAA13336406@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 10-01-2007 TIME: Wednesday, 17:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Studies of an intact virus by magic-angle spinning solid-state NMR\" SPEAKER: Prof. Amir Goldbourt , Department of Chemistry, Columbia University New York, NY 10027 USA (Candidate Lecture) ABSTRACT/COMMENTS: The structures of a number of filamentous bacteriophage viruses have been under study for many years by various spectroscopic methods. Much is understood about their structures, yet, surprisingly, key questions remain unanswered about interactions between the DNA and the protein capsid, about the interactions between subunits within the capsid, and about the conformation of the sidechains within the capsid. Pf1 is the one of the best studied of the filamentous phages from a structural point of view. Nevertheless, its molecularly detailed structure is still under debate. In this talk, Site-specific assignments are presented for resonances in the magic-angle spinning solid-state NMR spectra of the major coat protein subunit in the Pf1 virus. The assignment of over 90% of the 13C and 15N atoms is remarkable as there are 7300 helical subunits in the 36 MegaDalton virion. The special catabolism of the bacterial host of Pf1, pseudomonas aeruginosa, allows us to prepare samples with a unique backbone-labeling scheme. >From the analysis of the NMR data, we deduced important information regarding the conformation and symmetry of the subunit, which has an impact on current structural models of the virus. From physics at bgu.ac.il Sun Jan 7 13:10:17 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-11 Physics Colloquium Message-ID: <200701071110.NAA12760459@tzin.bgu.ac.il> Physics Colloquium DATE: 11-01-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Infrared transmitting AgClBr fibers and their applications SPEAKER: Abraham Katzir , Tel Aviv University, School of Physics and Astronomy ABSTRACT/COMMENTS: We have developed optical fibers which are based on crystalline AgClBr. The fibers are flexible, non-toxic, non-hygroscopic and highly transparent in the mid-IR (3-30microns). These fibers paved the way for advanced research and for novel applications: (1) Non - contact fiberoptic thermometry. (2) Laser bonding of biological tissues (e.g. for endoscopic surgery). (3) Fiberoptic mid-IR spectroscopy and its applications: a. Online monitoring water (e.g. environmental protection or homeland security). b. Early diagnosis of diseases (e.g. cancer or Alzheimer). c. Phase transition measurements (e.g. water/ice or protein coagulation). (4) Novel photonic crystal fibers. (5) Single Mode Fibers for Mid - IR astronomy (e.g. the search for the origin of life). (6) Rare earth doped AgClBr solid state lasers and fiber lasers (e.g. countermeasures against shoulder launched missiles). (7) Scanning Near Field Mid-IR Microscopy with a sub-wavelength resolution (e.g. for the study of biological cells or of integrated circuits). Refreshments are served at 3:20pm From Ibar at bgu.ac.il Sun Jan 7 13:31:10 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-09 Lasers Seminar Message-ID: <004901c7324f$548117a0$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 09-01-2007 TIME: 3:30pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: Molecular Dynamics of Ethene Isotopomers SPEAKER: Mr. Amir Zwielly, Department of Physics, Ben Gurion University of the Negev ABSTRACT/COMMENTS: -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070107/22bcb972/attachment.htm From gideonc at bgu.ac.il Sun Jan 7 17:50:04 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-11 Physics Colloquium Message-ID: <200701071550.RAA13558007@tzin.bgu.ac.il> Physics Colloquium DATE: 11-01-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Infrared transmitting AgClBr fibers and their applications SPEAKER: Prof. Abraham Katzir, Tel Aviv University, School of Physics and Astronomy. ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Domany.html Refreshments are served at 3:20pm From nano at bgu.ac.il Thu Jan 11 22:51:32 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-10 Nano Wires ECE seminar Message-ID: <00ab01c735c2$4769ebc0$1b0e4884@estinano> Nanotechnology workshop, Wednesday January 10, 16:10 in the ECE Seminar room. Building 26, Room 112 (first floor) Title : Nanowires: Growth, Physical Properties, and Devices Speaker: Dr. Ilan Shalish, Gordon McKay Laboratory for Applied Physics, Division of Engineering and applied Sciences, Harvard University Abstract: Nanowire is a small quasi-one-dimensional crystalline structure which is attracting research and funding around the globe in an unprecedented fashion. Is nanowire growth a promising nanotechnology? In this talk, I will address frequently asked questions about nanowires: How it all began, how nanowires grow and why. I will show some of our work on nitride and oxide semiconductor nanowires, their physical properties, their electronic and photonic devices (nanowire-channel field effect transistors, single-nanowire light emitting diodes), and discuss surprising effects of reduced-size and increased surface to volume ratio. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070111/5ee96f7c/attachment.htm From nano at bgu.ac.il Fri Jan 12 00:48:41 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-17 nanotechnology workshop Message-ID: <011f01c735d2$a4346550$1b0e4884@estinano> Nanotechnology workshop, Wednesday January 17, 12:00 building 29, room 306,Chemistry Department seminar room Title : Recent Progress in Accessing the Nanostructure of Liquid Systems by Cryo-TEM Speaker: Prof. Ishi Talmon Department of Chemical Engineering Technion Abstract: Cryo-TEM has become an indispensable tool to acquire high-resolution direct images of self-aggregating nanostrucutred liquids. The methodology that has been developed over the years allows us to capture the nanostructure in its native state of fixed concentration and temperature. A wide range of systems of low- and high-molecular weight solutes, synthetic and biological, has been studied already by the technique. While most cryo-TEM work has been done on aqueous systems, more recently the technique has been extended to non-aqueous solvents as well. The term ?cryo-TEM? actually refers to two techniques: direct-imaging cryo-TEM, by which a thin vitrified sample is examined by the TEM at cryogenic temperatures, and ?freeze-fracture-replication? cryo-TEM (FFR), by which a carbon-metal replica of the fractured fast-cooled specimen is examined at room temperature by the TEM. The two techniques are complementary, as I will explain in my talk. The presentation will begin with a brief description of the two techniques with emphasis on FFR, a most useful technique that is, unfortunately, quite rarely used nowadays. This will be followed by a discussion of the application of cryo-TEM to non-aqueous systems, pointing out the potential and the difficulties of this type of application. The application cryo-TEM to the study of the mechanism of mesophase formation will be described in the final part of the talk. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070112/02b78a4d/attachment.htm From hbaruch at bgu.ac.il Sun Jan 14 18:29:03 2007 From: hbaruch at bgu.ac.il (hbaruch@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-15 Condensed Matter Seminar Message-ID: <200701141629.SAA18797504@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 15-01-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: No seminar today SPEAKER: , ABSTRACT/COMMENTS: From physics at bgu.ac.il Mon Jan 15 09:19:30 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-17 Organic/Biophysics Chemistry Seminar Message-ID: <200701150719.JAA19957939@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 17-01-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Man’s Single Most Important Scientific Idea (according to Jacques Monod) and its Relevance to the Origin of Life Problem\" SPEAKER: Prof. Addy Pross, Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva, 84105, ISRAEL ABSTRACT/COMMENTS: In his classic book “Chance and Necessity” written 35 years ago, Jacques Monod makes a case for the view that Man’s single most important scientific idea in the ca. 100,000 years that he has populated the planet is that Nature is Objective, that there is no purpose in the laws of nature. The issue of whether the universe is purposeful and goal-directed (termed teleological) or not, has tormented mankind since the beginning of recorded history and continues to do so till today. In this lecture we will discuss Monod’s view and a brief history of this problem over the last 2500 years, how the issue has impacted on Science over the centuries, and discuss aspects of Monod’s paradox – how could living systems, which are undeniably purposeful, have emerged from a universe without purpose – from a chemical point of view. From gideonc at bgu.ac.il Mon Jan 15 11:41:47 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-18 Physics Colloquium Message-ID: <200701150941.LAA20021293@tzin.bgu.ac.il> Physics Colloquium DATE: 18-01-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Predicting outcome in cancer: Hope, Hype, Physics and ... Biology SPEAKER: Prof. Eytan Domany, Dept of Physics of Complex Systems, Weizmann Institute of Science. ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Domany.html Refreshments are served at 3:20pm From physics at bgu.ac.il Wed Jan 17 09:19:58 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-17 Organic/Biophysics Chemistry AT 17:00! Message-ID: <200701170719.JAA21627809@tzin.bgu.ac.il> Organic/Biophysics Chemistry AT 17:00! DATE: 17-01-2007 TIME: 17:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Man’s Single Most Important Scientific Idea (according to Jacques Monod) and its Relevance to the Origin of Life Problem\" SPEAKER: Prof. Addy Pross, Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva, 84105, ISRAEL ABSTRACT/COMMENTS: In his classic book “Chance and Necessity” written 35 years ago, Jacques Monod makes a case for the view that Man’s single most important scientific idea in the ca. 100,000 years that he has populated the planet is that Nature is Objective, that there is no purpose in the laws of nature. The issue of whether the universe is purposeful and goal-directed (termed teleological) or not, has tormented mankind since the beginning of recorded history and continues to do so till today. In this lecture we will discuss Monod’s view and a brief history of this problem over the last 2500 years, how the issue has impacted on Science over the centuries, and discuss aspects of Monod’s paradox – how could living systems, which are undeniably purposeful, have emerged from a universe without purpose – from a chemical point of view. From physics at bgu.ac.il Thu Jan 18 15:41:51 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-22 Special Seminar Message-ID: <200701181341.PAA22498296@tzin.bgu.ac.il> Special Seminar DATE: 22-01-2007 TIME: 11:00 PLACE: Physics Club room 002/29 TITLE: High temperature superconducting materials for power application in modern electromechanics. SPEAKER: Professor Lev K. Kovalev, , Moscow Aviation Institute (State Technical University) MAI, Russia. Dozor Visiting Fellow ABSTRACT/COMMENTS: From gideonc at bgu.ac.il Sun Jan 21 12:01:33 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-28 Special Physics Colloquium Message-ID: <200701211001.MAA24318613@tzin.bgu.ac.il> Special Physics Colloquium DATE: 28-01-2007 TIME: 3:30pm (Thu) PLACE: Physics Club TITLE: Application of the bulk HTS elements in electrical machines and magnetic levitation systems SPEAKER: Prof Dr. L. Kovalev, Moscow Aviation Institute, Moscow ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Kovalev.html Refreshments are served at 3:20pm From nano at bgu.ac.il Wed Jan 24 02:33:02 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-25 A symposium celebrating Baruch Horovitz's 60th birthday-program Message-ID: <01c301c73f4f$34c8f560$1b0e4884@estinano> Skipped content of type multipart/alternative-------------- next part -------------- A non-text attachment was scrubbed... Name: program.pdf Type: application/pdf Size: 507791 bytes Desc: not available Url : http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070124/536b3271/program.pdf From gideonc at bgu.ac.il Wed Jan 24 16:46:00 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-28 Special Physics Colloquium Reminder Message-ID: <200701241446.QAA27625652@tzin.bgu.ac.il> Special Physics Colloquium Reminder DATE: 28-01-2007 TIME: 3:30pm (Sunday) PLACE: Physics Club TITLE: Application of the bulk HTS elements in electrical machines and magnetic levitation systems SPEAKER: Prof Dr. L. Kovalev, Moscow Aviation Institute, Moscow ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Kovalev.html Refreshments are served at 3:20pm From physics at bgu.ac.il Sun Jan 28 08:38:59 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-28 Special Physics Colloquium - Today!!!! Message-ID: <200701280638.IAA30652816@tzin.bgu.ac.il> Special Physics Colloquium - Today!!!! DATE: 28-01-2007 TIME: 3:30pm (Sunday) PLACE: Physics Club TITLE: Application of the bulk HTS elements in electrical machines and magnetic levitation systems SPEAKER: Prof Dr. L. Kovalev, Moscow Aviation Institute, Moscow ABSTRACT/COMMENTS: 1. We review the main physical properties of low temperature (LTS) and high temperature (HTS) superconductors. The theoretical approach and experimental results for magnetization processes and hysteresis losses in bulk HTS materials with single domain and multi domain structure are presented. 2. The state of the art in the production of bulk and composed plate shaped HTS element and the new of types of HTS electrical machines is discussed. The main principles of the theory and the test results of the experiments with the new electrical motors using bulk HTS rotor element and output power in the range 1 ? 100 kW are given. 3. The application of bulk HTS element to high speed trains using magnetic levitation systems (Maglev) is discussed. The analytical approach to the calculation of levitation forces in magnetic HTS supports and the experimental results for carriages with magnetic HTS supports and useful load up to 600 kg are presented. Refreshments are served at 3:20pm From hbaruch at bgu.ac.il Sun Jan 28 13:11:45 2007 From: hbaruch at bgu.ac.il (hbaruch@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-01-29 Condensed Matter Seminar Message-ID: <200701281111.NAA30904337@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 29-01-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Nuclear spin dynamics in solids: implications of microscopic chaos SPEAKER: Dr. Boris Fine, Physics Department, University of Tennessee, Knoxville / Oak Ridge National Laboratory ABSTRACT/COMMENTS: Interaction between nuclear spins in solids forces each spin to perform a complicated dance in a time-dependent field created by neighboring spins. This leads to spin-spin relaxation observed by nuclear magnetic resonance (NMR). I briefly discuss the efforts to calculate NMR spin-spin relaxation from first principles, and then argue that the main obstacle to these efforts is the lack of the proper understanding of microscopic chaos. I proceed with presenting a theory, which invokes the notion of chaos and thereby predicts that NMR free induction decay and spin echoes observed in the same system have identical exponential long-time behavior. This prediction was shown to be quantitatively correct by a very recent NMR experiment on hyperpolarized solid xenon. Such a lack of dependence of the long-time decay on the initial spin configuration reveals a new fundamental property of nuclear spin dynamics in solids. Namely, the quantum time evolution operator of a macroscopic system of nuclear spins 1/2 has isolated eigenmodes, which govern the long-time relaxation towards equilibrium. These eigenmodes decay on the ballistic microscopic timescale. Therefore, their existence cannot be predicted using the standard approximations of statistical physics. Such eigenmodes, however, are very reminiscent of Pollicott-Ruelle resonances in classical chaotic systems, and, in fact, were predicted on the basis of this analogy. Their discovery thus constitutes a new step in establishing the foundations of statistical physics. It suggests that, even in the situations, when quasi-classical chaotic limit is not tenable, and the spacing between energy levels is not relevant to the observable properties, the notion of microscopic chaos can be defined for isolated many-body quantum systems at the level of Pollicott-Ruelle resonances. From hbaruch at bgu.ac.il Thu Feb 1 15:09:14 2007 From: hbaruch at bgu.ac.il (hbaruch@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-02-05 Condensed Matter Seminar Message-ID: <200702011309.PAA34114200@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 05-02-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Ultracold Heteronuclear Molecular Quantum Gases SPEAKER: Dr. Gabriel Kerner, Institut für Quantenoptik und Quanteninformation Austrian Academy of Sciences, Innsbruck, Austria ABSTRACT/COMMENTS: We are setting up a new experiment to study ultracold gas mixtures of fermionic Lithium, Potassium and Strontium. The system is a promising candidate for the study of new, intriguing many-body quantum systems, with strongly interacting Fermi gases consisting of atoms with unequal masses. Especially interesting is the formation of molecules, as well as their Bose-Einstein-Condensation. This allows the modeling of High-Tc Superconductors using three different heteronuclear systems (LiK, SrLi and SrK), as well as opens a door to a new kind of chemistry with coherent ensembles. The atoms, first collected in a two species magneto-optical trap, are transferred into an optical dipole trap for cooling to degeneracy and manipulation. Heteronuclear interactions are investigated using magnetic Feshbach resonances. These in turn allow to sensitively tune elastic collisional rates, and to achieve the formation of ultracold heteronuclear molecules. Long term goals include the exploration of optical resonances in alkaline/alkaline-earth mixtures and of the dipolar properties of heteronuclear molecules, as well as new schemes for coherent transfer into ground state molecules. From physics at bgu.ac.il Mon Feb 5 08:49:57 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-02-21 Special Chemical Physics Seminar Message-ID: <200702050649.IAA37192162@tzin.bgu.ac.il> Special Chemical Physics Seminar DATE: 21-02-2007 TIME: 16:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Molecular Search for localisation of matter waves with cold atoms SPEAKER: Prof. Yvan Castin, Laboratoire Kastler Brossel, Ecole normale superieure, Paris (France) ABSTRACT/COMMENTS: There are now several links between condensed matter physics and the physics of ultracold atomic gases. In particular, there is presently an intense experimental activity with cold atoms to observe and study effects of localisation of matter waves in a random potential. We will review these experimental efforts. We will then describe our proposal to create a disordered potential for an atomic matter wave by randomly trapping atoms of another species at the nodes of an opticallattice. The advantage of this realisation of disorder is that the scattering amplitude of the matter wave on a \'defect\' of the random potential can be tuned by an inter-species Feshbach resonance and can be made as large as necessary. We will discuss the prospects of this proposal to observe strong localization of matter waves, in particular in three dimensions. From dcohen at bgu.ac.il Wed Feb 7 09:18:10 2007 From: dcohen at bgu.ac.il (Doron Cohen) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-03-20 The Moshe Flato Lecture Series Message-ID: The Moshe Flato Lecture Series: Colloquia in Mathematics and Physics Tuesday, March 20, 9:45 am Joyce Goldman Auditorium, Ben-Gurion University http://physweb.bgu.ac.il/EVENTS/FLATO_2007 From physics at bgu.ac.il Mon Feb 12 14:07:24 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-02-19 Special Colloquium* Message-ID: <200702121207.OAA42619927@tzin.bgu.ac.il> Special Colloquium* DATE: 19-02-2007 TIME: 11AM PLACE: Physics club (Building 29, room 002) TITLE: * a talk for the Particles and Fields and Astrophysics and Cosmology groups Dark Energy and AWE (Abnormally Weighting Energy) SPEAKER: Jean-Michel ALIMI, Laboratoire Universe and Theories, Observatoire de Meudon, France ABSTRACT/COMMENTS: If the existence of dark energy can hardly be contested nowadays due to the accumulating observational evidences (SN, CMB, BOS, LSS...), the question of its physical origin has become a crucial problem not only for theoreticalcosmology but also for fundamental physics. We have developped a new interpretation of the dark energy in terms of an Abnormally Weighting Energy (AWE). This means that the dark energy does not couple to gravitation in thesame way as ordinary matter, yielding a violation of the waek and strong equivalence principles on cosmological scales. The resulting cosmologicalmechanism accounts for the Hubble diagram of type Ia supernovae in terms of both transcient cosmic acceleration without violation of the strong energy condition $p< - \\rho c^2 /3$ and a variation of the gravitational constant while still accounting for the present tests of general relativity. We discuss also how the AWE hypothesis could allow an unified description of dark matter and dark energy, and solve the coincidence problem. From physics at bgu.ac.il Mon Feb 19 10:25:27 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-02-19 Special Colloquium*- Reminder! Message-ID: <200702190825.KAA47603351@tzin.bgu.ac.il> Special Colloquium*- Reminder! DATE: 19-02-2007 TIME: 11AM PLACE: Physics club (Building 29, room 002) TITLE: * Joint Particles and Fields & Astrophysics and Cosmology Seminar Dark Energy and AWE (Abnormally Weighting Energy) SPEAKER: Jean-Michel ALIMI, Laboratoire Universe and Theories, Observatoire de Meudon, France ABSTRACT/COMMENTS: If the existence of dark energy can hardly be contested nowadays due to the accumulating observational evidences (SN, CMB, BOS, LSS...), the question of its physical origin has become a crucial problem not only for theoreticalcosmology but also for fundamental physics. We have developped a new interpretation of the dark energy in terms of an Abnormally Weighting Energy (AWE). This means that the dark energy does not couple to gravitation in thesame way as ordinary matter, yielding a violation of the waek and strong equivalence principles on cosmological scales. The resulting cosmologicalmechanism accounts for the Hubble diagram of type Ia supernovae in terms of both transcient cosmic acceleration without violation of the strong energy condition $p< - \\\\rho c^2 /3$ and a variation of the gravitational constant while still accounting for the present tests of general relativity. We discuss also how the AWE hypothesis could allow an unified description of dark matter and dark energy, and solve the coincidence problem. -------------------------------------------------------------------------------- From physics at bgu.ac.il Thu Feb 22 09:40:56 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-02-28 Organic/Biophysics Chemistry Seminar Message-ID: <200702220740.JAA50747861@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 28-02-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Investigation of surface processes of a polydiacetylene-based biosensor\" SPEAKER: Roman Volinsky, Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva, 84105, ISRAEL ABSTRACT/COMMENTS: Planar systems – monolayers and films – constitute a useful platform for studying membrane-active peptides. We analyze the interactions and aggregation properties of the antimicrobial pore-forming peptide – alamethicin at the air/water interface. Surface area/pressure isotherms, Brewster angle microscopy, and fluorescence-confocal microscopy provided detailed information on the morphologies and structural properties of the peptides and its effect on the film components. The pressure-area analysis and microscopy experiments facilitated visualization of the structural consequences of the peptide association at the air/water interface, with pure phospholipids films, and within mixed phospholipid/diacetylene films. The analysis exposed the kinetic features and the interplay between the peptide aggregates and film constituents. In general, film analysis emphasized the effects of lipid layers in promoting peptide association and aggregation at the air/water interface. Importantly, the data demonstrated that in many cases peptide domains are immiscible within the phospholipid monolayers, suggesting that this behavior contributes to the biological actions of membrane-active antimicrobial peptides. In particular, the results demonstrate the use of phospholipid/polydiacetylene (PDA) film assemblies for studying membrane-peptide association and interactions within two-dimensional films. From Ibar at bgu.ac.il Thu Feb 22 10:00:16 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-03-27 Lasers Seminar Message-ID: <03a201c75657$7cf987e0$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 27-03-2007 TIME: 3:30pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: Single-molecule spectroscopy and the physics of proteins SPEAKER: Prof. Gilad Haran, Chemical Physics Department, Weizmann Institute of Science, Rehovot 76100, Israel ABSTRACT/COMMENTS: Fluorescence spectroscopy on the single-molecule level can provide a unique view of proteins. In this lecture I will describe two recent experiments where single-molecule techniques, from FRET to fluorescence correlation spectroscopy, have been applied in order to study protein dynamics. First, I will show that the coil-globule transition, a hallmark of polymer physics, is of major importance for the description of denatured states of proteins. Second, I will attempt to understand protein-protein association in complex liquids by dissecting the reaction into its various components, including translational and rotational diffusion. These experiments open a window on the role of excluded volume (entropic) interactions in protein dynamics. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070222/f0536deb/attachment.htm From jung at bgu.ac.il Thu Feb 22 14:06:48 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:24 2009 Subject: [Phys-seminars] 2007-02-26 Condensed Matter Seminar Message-ID: <200702221206.OAA51163994@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 26-02-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Cavity QED with cold atoms and chip-based microresonators SPEAKER: Dr. Barak Dayan, California Institute of Technology ABSTRACT/COMMENTS: Cavity Quantum Electrodynamics (cavity QED) provides a means for quantum state transfer between light and matter. In particular, strong coupling between single atoms and single photons (i.e. coupling that is stronger than all the dissipative processes in the system) has been achieved so far only with Fabry-Perot resonators. Although Fabry-Perot based systems have succeeded in demonstrating advanced cavity QED phenomena such as single-photons on demand and photon-blockade, a considerable effort has been made to achieve similar phenomena with monolithic, chip-based microresonators. In my talk I will present our recent demonstration of strong coupling between single Cs atoms and such a toroidal microresonator on a chip. Such microresonators are manufactured by standard lithographic techniques and are efficiently coupled to optical fibers, and thus offer a promising step towards scalable quantum networks. From hbaruch at bgu.ac.il Sun Feb 25 16:35:35 2007 From: hbaruch at bgu.ac.il (hbaruch@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-02-28 Electrical Engineering & CM seminar Message-ID: <200702251435.QAA53434908@tzin.bgu.ac.il> Electrical Engineering & CM seminar DATE: 28-02-2007 TIME: 14:10 (Wednesday) PLACE: Seminar room: Building 26, Room 112 (first floor) TITLE: Linking Morphology and Performance in Polymer solar cells SPEAKER: Dr. Rafi Shikler, Cavendish labs, University of Cambridge ABSTRACT/COMMENTS: Plastic electronic is a relatively new and rapidly growing field. Current products include devices such as polymer light emitting diodes, transistors, memories, smart cards and solar cells. Most of these products have comparable performance to solid-state devices, however solar cells are still lagging far behind despite their economical potential. The study presented here is focused on understanding the role of polymer/polymer interfaces in organic solar cells and on new ways to improve their performance. I present a framework for the calculation of light absorption in multi-component polymer photocells. The model shows how carefully designed device structures can lead to a large enhancement in the light absorption by the device. I also present experimental results that show the effect of device morphology on its performance, in particular the effect of time evolution of composition next to polymer/polymer interface on device efficiency. From nano at bgu.ac.il Mon Feb 26 12:52:47 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-02-28 nanotechnology workshop-NO SEMINAR Message-ID: <009001c75994$405df600$1b0e4884@estinano> There will not be a seminar on 28.02.07 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070226/200c758b/attachment.htm From gideonc at bgu.ac.il Mon Feb 26 17:38:01 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-08 Physics Colloquium Message-ID: <200702261538.RAA54380249@tzin.bgu.ac.il> Physics Colloquium DATE: 08-03-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Active Elasticity and Interactions of Cells in Gels SPEAKER: Prof. S. A. Safran , Dept. Materials and Interfaces, Weizmann Institute of Science ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Safran.html Refreshments are served at 3:20pm From physics at bgu.ac.il Tue Feb 27 11:25:28 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-11 A Special Lecture Series 11-16/3 2007 Message-ID: <200702270925.LAA55147343@tzin.bgu.ac.il> A Special Lecture Series 11-16/3 2007 DATE: 11-03-2007 TIME: PLACE: Will be Announced! TITLE: Quantum Impurities in and out of Equilibrium SPEAKER: Prof. Natan Andrei, Rutgers University ABSTRACT/COMMENTS: 6 lectures, one or two per day, from Sunday, March 11th, 2007, to Thursday, March 15th, 2007, (check the webpage http://physweb.bgu.ac.il/EVENTS/natan2007 for complete schedule) Natan Andrei is THE internationally leading expert on Bethe-Ansatz solutions of quantum impurity models. The summer-school style lectures will aim to introduce an audience of non-experts to the Bethe-Anstaz method and to his recent advances in using a newly developed nonequilibrium Bethe Ansatz to solve nonequilibrium quantum impurity problems. From physics at bgu.ac.il Tue Feb 27 11:28:55 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-02-28 Astrophysics and Cosmology Seminar Message-ID: <200702270928.LAA54868866@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 28-02-2007 TIME: 12:00 noon (Wed) PLACE: Physics club (Building 29, room 002) TITLE: Analysis of the magnetorotational instability in a thin-gap Taylor-Couette model SPEAKER: Dr. Orkan Umurhan , (Technion) ABSTRACT/COMMENTS: The magnetorotational instability (MRI) is broadly accepted as the source of turbulence in astrophysical systems exhibiting strong shear. We present here a detailed analysis of the development of MRI in a model environment that has features similar to ongoing terrestrial experiments seeking to demonstrate the mechanism. We perform a linear and weakly nonlinear analysis of this instability with a background vertical magnetic field. We find that the amount of transport decays with decreasing magnetic Prandtl number. We offer some reflections upon these results and how they relate to the astrophysical problem. If time permits some words will be mentioned about the recently discovered helical field instability. From gideonc at bgu.ac.il Tue Feb 27 16:09:38 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-01 Physics Colloquium Message-ID: <200702271409.QAA55154093@tzin.bgu.ac.il> Physics Colloquium DATE: 01-03-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: There\'s no Colloquium this week because of the holiday SPEAKER: , ABSTRACT/COMMENTS: Refreshments are served at 3:20pm From Ibar at bgu.ac.il Wed Feb 28 08:20:54 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-06 Lasers Seminar Message-ID: <000801c75b00$9a46fe60$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 06-03-2007 TIME: 3:30pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: Electronic properties of solids manifested in Raman scattering spectroscopy SPEAKER: Dr. Tsachi Livneh, Department of Physics Nuclear Research Center Negev (NRCN) ABSTRACT/COMMENTS: Raman scattering in solids may be regarded as a form of modulation spectroscopy where atomic vibrations modulate the electric susceptibility at the phonon frequency. We shall explore the manifestation of electronic structure modifications in the resonant Raman scattering from various systems. The sensitivity to the formation of lattice defects which produce new electronic states in the band gap will be demonstrated for GaN nanowires [1]. Pressure induced changes in the interaction of electrons with longitudinal optic (LO) phonons will be shown for UO2 [2, 3] and shifts in the resonant exciton energy will be argued to be manifested in the Raman spectrum of MoS2. The sensitivity of Raman to structural properties of solids may also be briefly discussed if time will permit. [1] T. Livneh, J.P. Zhang, G.S. Cheng and M. Moskovits, Phys. Rev. B 74, 035320 (2006). [2] T. Livneh and E. Sterer, Phys. Rev. B 73, 085118 (2006). [3] T. Livneh, Phys. Rev. B, submitted. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070228/90226053/attachment.htm From jung at bgu.ac.il Wed Feb 28 12:47:30 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-05 Condensed Matter Seminar Message-ID: <200702281047.MAA55829570@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 05-03-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Photoinduced phenomena in glassy semiconductors: physics and applications SPEAKER: Professor Victor Lyubin, Physics Department Ben Gurion University ABSTRACT/COMMENTS: Peculiarities of a large class of semiconductors – chalcogenide glassy semiconductors will be discussed. Main accent will be made on specific photo-induced phenomena: photo-structural transformations, photo-induced diffusion of metals and photo-induced anisotropy, characteristic for the glassy semiconductors. Very new experimental results on the superlinear photoresist effect and transient photo-refraction effect will be discussed. Different applications of photo-induced phenomena in glassy semiconductors in modern electro-optics will be considered. Several developed micro-optical devices (micro-lens-,micro-mirror-, micro-prism – arrays) and photonic crystals will be considered. From physics at bgu.ac.il Mon Mar 5 10:36:01 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-07 Organic/Biophysics Chemistry Seminar Message-ID: <200703050836.KAA59609454@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 07-03-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Monitoring Organization and Dynamics of Membranes and Proteins using the Wavelength-Selective Fluorescence Approach\" SPEAKER: Prof. Amitabha Chattopandhyay, אורח קרן Dozor Fellowship Group Leasder Center for Cellular&Molecular Biology India ABSTRACT/COMMENTS: Wavelength-selective fluorescence comprises a set of approaches based on the red edge effect in fluorescence spectroscopy which can be used to directly monitor the environment and dynamics around a fluorophore in a complex biological system. A shift in the wavelength of maximum fluorescence emission toward higher wavelengths, caused by a shift in the excitation wavelength toward the red edge of absorption band, is termed red edge excitation shift (REES).1-3 This effect is mostly observed with polar fluorophores in motionally restricted media such as very viscous solutions or condensed phases where the dipolar relaxation time for the solvent shell around a fluorophore is comparable to or longer than its fluorescence lifetime. REES arises from slow rates of solvent relaxation (reorientation) around an excited state fluorophore which is a function of the motional restriction imposed on the solvent molecules in the immediate vicinity of the fluorophore. Utilizing this approach , it becomes possible to probe the mobility parameters of the environment itself (which is represented by the relaxing solvent molecules) using the fluorophore merely as a reporter group. Further, since the ubiquitous solvent for biological systems is water, the information obtained in such cases will come from the otherwise \'optically silent\' water molecules. This makes REES and related techniques extremely useful since hydration plays a crucial modulatory role in a large number of important cellular events, including lipid-protein interactions and ion transport. The application of REES and related techniques (wavelength-selective fluorescence approach) as a powerful tool to monitor organization and dynamics of cytoskeletal proteins such as spectrin, and of probes and peptides bound to membranes, micelles, and reverse micelles will be the focus of the talk. .Demchenko, A.P. (2002) Luminescence 17: 19-42 .1 . Chattopadhyay, A. (2003) Chem. Phys. Lipids 122: 3-17 .2 Raghuraman, H., Kelkar, D.A., and Chattopadhyay, A. (2005) In Reviews in Fluorescence .3 2005 . Vol. 2. Geddes, C.D., and Lakowicz, J.R., Eds., pp. 199-222, Springer, New York. From nano at bgu.ac.il Mon Mar 5 14:22:35 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-07 nanotechnology workshop Message-ID: <010e01c75f20$f54c02a0$1b0e4884@estinano> Nanotechnology workshop, Wednesday March 7, 12:00 building 29, room 306,Chemistry Department seminar room Title : will be announced later Speaker: Dr. Slava Freger The Zuckerberg Institute for Water Research Sede-Boqer Campus, BGU -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070305/188b4728/attachment.htm From nano at bgu.ac.il Wed Mar 7 10:23:58 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-07 nanotechnology workshop Message-ID: <003d01c76091$f405e560$1b0e4884@estinano> ----- Original Message ----- From: Nano To: nano Sent: Monday, March 05, 2007 2:22 PM Subject: 2007-03-07 nanotechnology workshop Nanotechnology workshop, Wednesday March 7, 12:00 building 29, room 306,Chemistry Department seminar room Title : Synthetic composite membranes: the long way to perfection Speaker: Dr. Slava Freger The Zuckerberg Institute for Water Research Sede-Boqer Campus, BGU Abstract: Modern separation membranes owe their performance to a decades-long and largely empirical effort that led to a unique combination of permeability, selectivity and strength. This combination has been achieved in the composite structure combining a thin polyamide layer (20-200 nm) supported by an asymmetrically porous film. Such membranes have been manufactured on a large scale for over two decades, however, surprisingly, they still pose many questions regarding the structure, separation mechanism and possible ways to improve and diversify the existing membrane arsenal. Using a theoretical analysis and direct observations we revealed that the polyamide layer possesses nanoscale substructures whose origin could be tracked back to the process of membrane formation (interfacial polymerization). These findings help to improve our understanding of the separation mechanism and guide the search for better membranes. In particular, we explore electrochemical polymerization as a possible way to prepared new types of membranes. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070307/8110db5c/attachment.htm From jung at bgu.ac.il Wed Mar 7 11:31:59 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-12 Condensed Matter Seminar Message-ID: <200703070931.LAA62027737@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 12-03-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Disorder induced phase coexistence in bulk doped manganites and its suppression in nanometer sized crystals: The case of La0.9Ca0.1MnO3 SPEAKER: Evgeny Rozenberg, Ben Gurion University, Department of Physics ABSTRACT/COMMENTS: X-band Electron Magnetic Resonance together with dc and ac magnetic measurements were explored for comparative study of magnetic ordering in bulk and nanometer-sized La0.9Ca0.1MnO3 single crystals. A dramatic difference between such orderings has been revealed. Namely, bulk crystal possesses mixed magnetic state constituted by coexisting canted antiferromagnetic A-type matrix and nanometer sized ferromagnetic clusters. The same compound in the nano crystalline form shows mainly ferromagnetic ordering. The complementary study of structural state and crystallinity of the considered samples together with the model fittings of Electron Paramagnetic Resonance data were used to clarify the reason for the above mentioned strong difference in magnetic orderings. The results obtained allow one to conclude that the change in magnetic order has an intrinsic nature and is not induced by non-stoichiometry. It appears that the size reduction of La0.9Ca0.1MnO3 crystals down to nanometer siz e scale leads to the improvement of its chemical homogeneity and crystallinity. This effect induces the transition from inhomogeneous confinement of charge carriers in chemically disordered bulk crystal to their mobility within impurity-like band in more homogeneous nano-crystals and results in the above noted change in magnetic ordering. Thus, a realistic model describing size reduction effect on magnetic order in doped manganites is introduced for the first time. These results directly demonstrate a strong impact of chemical/magnetic disorder on magnetic ordering and phase diagram of doped manganites, which must be taken into account in theoretical models of phase coexistence in doped manganites. From nano at bgu.ac.il Wed Mar 7 12:17:03 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-14 nanotechnology workshop Message-ID: <00c301c760a1$c08aee00$1b0e4884@estinano> Nanotechnology workshop, Wednesday March 14, 12:00 building 29, room 306,Chemistry Department seminar room Title : The "0.7 anomaly" in quantum point contacts: the puzzle and its resolution. Speaker: Prof. Yigal Meir Physics Department Ben-Gurion University -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070307/e68fdc90/attachment.htm From physics at bgu.ac.il Thu Mar 8 12:59:16 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-14 Organic/Biophysics Chemistry Seminar Message-ID: <200703081059.MAA62959978@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 14-03-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Investigation of membrane interactions of pharmacologically active compounds by a novel biomimetic colorimetric sensor\" SPEAKER: Marina Katz, (Doctoral Lecture) ABSTRACT/COMMENTS: Elucidation of interactions between pharmacological compounds with the cell membrane plays major roles in determination of the mechanisms of action of membrane-active compounds. We demonstrate applications of a new biomimetic membrane sensor composed of conjugated polydiacetylene with synthetic or/and natural lipids or fragments of nature membrane which undergoes visible and quantifiable blue-to-red color transitions upon cell membrane perturbation. This information obtained by the colorimetric assay facilitates \"color coding\" that could discern between three primary types of membrane-permeation profiles: bilayer- surface attachment, membrane penetration, and absence of lipid interactions. Application of several bio-analytical techniques, such as spectroscopic quenching analysis, small angle X-ray scattering and differential scanning calorimetry measurements supported the interpretation of the colorimetric data. From physics at bgu.ac.il Thu Mar 8 13:02:49 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-15 Physics Colloquium Message-ID: <200703081102.NAA62908200@tzin.bgu.ac.il> Physics Colloquium DATE: 15-03-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Superradiance, mesoscopic fluctuations and localization in cold atomic gases SPEAKER: Eric Akermmans , Department of Physics , Technion ABSTRACT/COMMENTS: We discuss three issues related to Anderson localization (either weak or strong) of photons or matter waves in cold atomic gases. The first issue deals with the interplay of superradiance (more generally cooperative effects) and coherent multiple scattering and its implication on the universality of the localization transition. Then, we shall discuss the enhancement induced by disorder on photon correlations in the weak localization regime and its implication for atomic spectroscopy. Finally, we shall move to the problem of one-dimensional localization of matter waves and the effect of nonlinearities. Refreshments are served at 3:20pm From gideonc at bgu.ac.il Thu Mar 8 13:57:25 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-08 Physics Colloquium - Reminder Message-ID: <200703081157.NAA63003970@tzin.bgu.ac.il> Physics Colloquium - Reminder DATE: 08-03-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Active Elasticity and Interactions of Cells in Gels SPEAKER: Prof. S. A. Safran , Dept. Materials and Interfaces, Weizmann Institute of Science ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Safran.html Refreshments are served at 3:20pm From Ibar at bgu.ac.il Thu Mar 8 14:06:51 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-13 Lasers Seminar Message-ID: <004101c7617a$41c14cc0$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 13-03-2007 TIME: 3:30pm (Tue) TITLE: There is no seminar this week. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070308/3e9cb071/attachment.htm From band at bgu.ac.il Fri Mar 9 11:00:51 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-14 Physical Chemistry Seminar Message-ID: <200703090900.LAA63771938@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 14-03-2007 TIME: 4:00 PM (Wed) PLACE: Chemistry Club (Building 29, room 306) TITLE: Alignment and entanglement of molecules by lasers SPEAKER: Professor Nimrod Moiseyev, Technion ABSTRACT/COMMENTS: Surprisingly, two qualitatively different forms of the induced dipole Hamiltonian appear in the theoretical literature on alignment of molecules by a laser. We prove that there is no contribution of the permanent dipole moment to the Born-Oppenheimer time dependent Hamiltonian and therefore even heterenuclear diatoms are aligned/entangled by lasers. High order harmonic generation spectra (HGS) measurements will enable us to follow the transition from entangled to oriented molecule, indicated by the transition from odd HGS only to a mixed odd and even HGS. From band at bgu.ac.il Fri Mar 9 11:05:10 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-21 Physical Chemistry Seminar Message-ID: <200703090905.LAA63720354@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 21-03-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry Club (Building 29, room 306) TITLE: Coherent Addition of Lasers SPEAKER: Professor Nir Davidson , Weizmann Institute of Science ABSTRACT/COMMENTS: In order to obtain high output powers and good beam quality, a unique approach for efficient phase locking and coherent addition of laser beams was developed. Self-phase-locking and coherent addition is achieved by use of intra-cavity interferometric combiners. The approach is demonstrated experimentally with multi-channel solid state lasers resonator (including 2, 3, 4, 5, 9, 16 and 25 independent channels), and in fiber lasers. In all cases more than 90% combining efficiency was achieved while preserving the beam quality of a single channel. From physics at bgu.ac.il Sun Mar 11 08:44:11 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-14 Astrophysics and Cosmology Seminar Message-ID: <200703110644.IAA65169036@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 14-03-2007 TIME: 12:00 noon (Wed) PLACE: Physics club (Building 29, room 002) TITLE: Acceleration and Heating of The Solar Wind SPEAKER: Dr. Leon Ofman, GSFC/NASA and Catholic University ABSTRACT/COMMENTS: From Ibar at bgu.ac.il Mon Mar 12 08:20:28 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-14 Lasers Seminar Message-ID: <012801c7646e$875bd0b0$d10f4884@ilap> Joint Physical Chemistry and Lasers Seminar DATE: 14-03-2007 TIME: 4:00 PM (Wed) PLACE: Chemistry Club (Building 29, room 306) TITLE: Alignment and entanglement of molecules by lasers SPEAKER: Professor Nimrod Moiseyev, Technion ABSTRACT/COMMENTS: Surprisingly, two qualitatively different forms of the induced dipole Hamiltonian appear in the theoretical literature on alignment of molecules by a laser. We prove that there is no contribution of the permanent dipole moment to the Born-Oppenheimer time dependent Hamiltonian and therefore even heterenuclear diatoms are aligned/entangled by lasers. High order harmonic generation spectra (HGS) measurements will enable us to follow the transition from entangled to oriented molecule, indicated by the transition from odd HGS only to a mixed odd and even HGS. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070312/4e70da6a/attachment.htm From gideonc at bgu.ac.il Mon Mar 12 14:08:19 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-15 Physics Colloquium Reminder Message-ID: <200703121208.OAA66259541@tzin.bgu.ac.il> Physics Colloquium Reminder DATE: 15-03-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Superradiance, mesoscopic fluctuations and localization in cold atomic gases SPEAKER: Prof. Eric Akkermans , Department of Physics , Technion ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Erik.html Refreshments are served at 3:20pm From Ibar at bgu.ac.il Wed Mar 14 10:58:41 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-20 Lasers Seminar Message-ID: <032e01c76616$f66b9db0$d10f4884@ilap> Skipped content of type multipart/alternative-------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/jpeg Size: 8584 bytes Desc: not available Url : http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070314/2f778589/attachment.jpg From nano at bgu.ac.il Wed Mar 14 12:10:48 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-21 nanotechnology workshop Message-ID: <00e901c76621$0ae51e10$1b0e4884@estinano> Nanotechnology workshop, Wednesday March 21, 12:00 building 29, room 306,Chemistry Department seminar room Title : Formation, Characterization and Applications of Organic and Inorganic Nanometric Films Speaker: Prof. Daniel Mandler Department of Inorganic and Analytical Chemistry the Hebrew University of Jerusalem Abstract: During the last years we have developed different approaches for the formation of thin films, ranging from monolayer to sub-micrometer thick polymeric films. These layers were made of organic (self-assembled monolayers and conducting polymers) and inorganic materials (sol-gel materials) and used in different applications, such as sensing, corrosion inhibition, coating medical devices and for basic research. The aim of this seminar is to give a wide view of the different strategies adopted in structuring mostly the solid-liquid interface as a means of tailoring its physical and chemical properties. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070314/4be8759e/attachment.htm From jung at bgu.ac.il Wed Mar 14 13:53:15 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-19 Condensed Matter Seminar Message-ID: <200703141153.NAA67948966@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 19-03-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: The physics of gene delivery lipid-DNA complexes SPEAKER: Oded Farago, Department of Biomedical Engineering Ben Gurion University of the Negev ABSTRACT/COMMENTS: We present a computer model which captures the self-assembly of cationic liposomes complexed with DNA - a promising synthetically based nonviral carrier of DNA for gene therapy. The model is a full molecular description that allows the study of molecular self-assembly from structural disorder. Computational simplifications necessary for efficiency are introduced through a coarse-grained representation of the intra-molecular atomic details. The inter-molecular potentials are designed to mimic the hydrophobic effect without the explicit presence of solvent. Thus, the approach carefully balances the need for molecular detail with computational practicality in a manner that allows for solvent-free simulations of complex self-assembly over long enough time scales to address experimental reality. In addition to showing spontaneous self-assembly of cationic lipid-DNA complexes, the broad utility of the model (which extends a coarse-grained lipid bilayer model) is illustrated by demonstrating excellent agreement with X-ray diffraction experimental data for the dependence of the interaxial distance between DNA chains on the fraction of charged lipids. At high concentrations of charged lipids, the large electrostatic pressure induce the formation of pores in the membranes through which the DNA molecules may escape the complex. We suggest that this is the origin of recently observed enhanced transfection efficiency of lamellar CL-DNA complexes at high charge densities. We also find that the presence of multivalent cationic lipids tends to stabilize the system by inducing attractive interactions between the DNA rods. From physics at bgu.ac.il Thu Mar 15 12:42:38 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-19 Particles and Fields Seminar Message-ID: <200703151042.MAA68051182@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 19-03-2007 TIME: 10:00pm (Mon) PLACE: Physics club (Building 29, room 002) TITLE: \"Chiral Anomalies\" SPEAKER: Ilya Gurwich, ABSTRACT/COMMENTS: From physics at bgu.ac.il Mon Mar 19 13:38:10 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-21 Organic/Biophysics Chemistry Seminar Message-ID: <200703191138.NAA71908324@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 21-03-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"Protein engineering using directed evolution methodologies\" SPEAKER: Dr. Amir Aharoni, Department of Life Sciences, Ben-Gurion University of the Negev ABSTRACT/COMMENTS: Engineering of proteins with new functions is important for gaining an understanding of protein structure, function and evolution and for a variety of practical applications such as developing enzymes for chemical synthesis, biomedical diagnostics and even therapeutic applications. Over the past few years, directed evolution has emerged as a powerful methodology for generating enzyme variants with improved catalytic activities, new substrate specificity, and activity under extreme conditions such as elevated temperatures or highly acid or alkaline environments. By mimicking natural evolution, directed evolution aims to generate proteins with new activities by screening or selecting for the desired functions from a large ensemble of random protein mutants. I will present the principles and applications of directed evolution methodologies for the generation of enzymes with increased catalytic efficiencies and new specificities. From gideonc at bgu.ac.il Mon Mar 19 16:52:39 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-22 Physics Colloquium Message-ID: <200703191452.QAA71992283@tzin.bgu.ac.il> Physics Colloquium DATE: 22-03-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Physical Aspects of the Origin of Life Problem SPEAKER: Prof. Albert Libchaber, Rockefeller University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Libchaber.html Refreshments are served at 3:20pm From jung at bgu.ac.il Tue Mar 20 12:10:09 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-26 Condensed Matter Seminar Message-ID: <200703201010.MAA72902717@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 26-03-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: \"Ferromagnetic resonance in epitaxial La-Sr-Mn-O films\" SPEAKER: Dr. Michael Golosovsky, The Racah Institute of Physics, The Hebrew University of Jerusalem ABSTRACT/COMMENTS: We discuss the ferromagnetic resonance technique in oblique magnetic field and show how one can use it to measure various magnetic properties of thin film samples. In particular, in our studies of epitaxial LSMO films we observe (i) uniform ferromagnetic resonance (FMR), (ii) spin-wave resonances, and (iii) nonresonant microwave absorption. The FMR and spin-wave resonances yield temperature dependence of the anisotropy field and of the spin stiffness. The spin stiffness in thin films is in fair agreement with the results of the inelastic neutron scattering on a single crystal of the same composition. We show that the nonresonant microwave absorption originates from the colossal magnetoresistance. Our contactless measurement of colossal magnetoresistance verifies that it is nearly isotropic. We also observe a zero-field absorption with very peculiar angular dependence and attribute it to the ferromagnetic resonance in the multidomain state. From Ibar at bgu.ac.il Tue Mar 20 17:12:10 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-21 Lasers Seminar Message-ID: <001001c76b02$21d062c0$d10f4884@ilap> Joint Physical Chemistry and Lasers Seminar DATE: 21-03-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry Club (Building 29, room 306) TITLE: Coherent Addition of Lasers SPEAKER: Professor Nir Davidson , Weizmann Institute of Science ABSTRACT/COMMENTS: In order to obtain high output powers and good beam quality, a unique approach for efficient phase locking and coherent addition of laser beams was developed. Self-phase-locking and coherent addition is achieved by use of intra-cavity interferometric combiners. The approach is demonstrated experimentally with multi-channel solid state lasers resonator (including 2, 3, 4, 5, 9, 16 and 25 independent channels), and in fiber lasers. In all cases more than 90% combining efficiency was achieved while preserving the beam quality of a single channel. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070320/f8f24620/attachment.htm From Ibar at bgu.ac.il Tue Mar 20 17:28:44 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-29 Lasers Seminar Message-ID: <002c01c76b04$72fcf490$d10f4884@ilap> Please notice the special date and time ANNOUNCEMENT==> Lasers Seminar DATE: 29-03-2007 TIME: 10:30 am (Thu) PLACE: Chemistry Club (Building 29, room 306) TITLE: What narrow band diode lasers and femtosecond fiber lasers have in common? SPEAKER: Dr. Wilhelm Kaenders, Co-Founder and President of TOPTICA Photonics AG, ABSTRACT/COMMENTS: Narrow band lasers have been the key tool for high resolution spectroscopy and frequency metrology alike for decades. Using nonlinear schemes of higher harmonic generation (frequency doubling, trippling, etc) but also phase-controlled frequency subdivision were the techniques employed for decades in frequency chains in all major national laboratories to realise time and frequency standards based on the Cs atomic clock, but also other laser-cooled atomic or ionic traps. Multiple phase-controlled laser frequencies were superpositioned for the first time to tailor short pulses as early as 1993 (R. Wynands et al). However, it took a few more years to turn the notion around and combined with the technical advances in the ultrashort pulse generation to fully acknowledge that a femtosecond laser pulse can be described as and practically also is the phase-locked superposition of hundred thousands of narrowband cw lasers running in the same resonator, giving birth to a new technique, refered to as "frequency comb technique with self-referencing" as the new tool of practical frequency metrology. In my talk I will try to point out TOPTICA's envolvement into this field as a commercial player since 1995, starting from tunable diode lasers and diode amplifiers and resulting today in the offering of fs-fiber-based supercontinua phase-coherently spanning more than 4 optical octaves from 500 to more than 2000 nm. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070320/b176fbe9/attachment.htm From nano at bgu.ac.il Wed Mar 21 12:08:49 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-28 nanotechnology workshop Message-ID: <003301c76ba0$ec0999a0$1b0e4884@estinano> Nanotechnology workshop, Wednesday March 28, 12:00 building 29, room 306,Chemistry Department seminar room Title : Coordination Self-Assembly of Branched Nanostructures Speaker: Prof. Israel Rubinstein Department of Materials and Interfaces Weizmann Institute of Science -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070321/93ba51c9/attachment.htm From nano at bgu.ac.il Wed Mar 21 16:28:28 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-28 nanotechnology workshop Message-ID: <001501c76bc5$3152d570$1b0e4884@estinano> ----- Original Message ----- From: Nano To: nano Sent: Wednesday, March 21, 2007 12:08 PM Subject: 2007-03-28 nanotechnology workshop Nanotechnology workshop, Wednesday March 28, 12:00 building 29, room 306,Chemistry Department seminar room Title : Coordination Self-Assembly of Branched Nanostructures Speaker: Prof. Israel Rubinstein Department of Materials and Interfaces Weizmann Institute of Science Abstract: Layer by layer (LbL) assembly of multilayer films on surfaces offers control over film thickness and composition on the nm scale. We have shown its applicability to the preparation of coordination multilayers on gold substrates, based on bishydroxamate ligands and tetravalent metal ions. Following assembly of a bishydroxamate disulfide anchor monolayer on gold surface, multilayer growth proceeded by alternate binding of tetrahydroxamate ligand molecules and Zr(IV) ions. This concept is extended to nanostructures based on branched building blocks, i.e., branched ligand molecules as well as gold nanoparticles (NPs) derivatized with ion-binding molecules. LbL growth of branched structures proceeds with high regularity. Branched multilayers display improved stiffness and a defect self-repair mechanism, attributed to lateral cross-linking. Spacing of the anchor sites on the gold substrate affords coordination dendrimers, grown from the surface using the same methodology. Ligand-derivatized Au NPs can be similarly assembled to afford ordered multilayer films. Hybrid multilayers combining branched ligand molecules and NPs show special electrical properties. Application of the same scheme to coordination LbL growth on oxide substrates (glass, Si/SiO2) is also feasible. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070321/18b45780/attachment.htm From Ibar at bgu.ac.il Mon Mar 26 12:48:51 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-29 Lasers Seminar Message-ID: <047c01c76f94$57c68760$d10f4884@ilap> ANNOUNCEMENT==> Please notice that there is no Lasers seminar on Tuesday 29.03.2007. There is a special Lasers Seminar on DATE: 29-03-2007 TIME: 10:30 am (Thu) PLACE: Building 90, room 127 TITLE: What narrow band diode lasers and femtosecond fiber lasers have in common? SPEAKER: Dr. Wilhelm Kaenders, Co-Founder and President of TOPTICA Photonics AG, ABSTRACT/COMMENTS: Narrow band lasers have been the key tool for high resolution spectroscopy and frequency metrology alike for decades. Using nonlinear schemes of higher harmonic generation (frequency doubling, trippling, etc) but also phase-controlled frequency subdivision were the techniques employed for decades in frequency chains in all major national laboratories to realise time and frequency standards based on the Cs atomic clock, but also other laser-cooled atomic or ionic traps. Multiple phase-controlled laser frequencies were superpositioned for the first time to tailor short pulses as early as 1993 (R. Wynands et al). However, it took a few more years to turn the notion around and combined with the technical advances in the ultrashort pulse generation to fully acknowledge that a femtosecond laser pulse can be described as and practically also is the phase-locked superposition of hundred thousands of narrowband cw lasers running in the same resonator, giving birth to a new technique, refered to as "frequency comb technique with self-referencing" as the new tool of practical frequency metrology. In my talk I will try to point out TOPTICA's envolvement into this field as a commercial player since 1995, starting from tunable diode lasers and diode amplifiers and resulting today in the offering of fs-fiber-based supercontinua phase-coherently spanning more than 4 optical octaves from 500 to more than 2000 nm. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070326/44243752/attachment.htm From physics at bgu.ac.il Tue Mar 27 14:40:38 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-28 Organic/Biophysics Chemistry Seminar Message-ID: <200703271240.OAA77964382@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 28-03-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"NH4Cl induces NO production in ciliary cells\" \"Functional overlap between microtubule-based molecular motors during anaphase B spindle elongation\" SPEAKER: Margarita Eisenberg, Natalia Movshovich, Department of Chemistry, Ben-Gurion University of the Negev ABSTRACT/COMMENTS: From nano at bgu.ac.il Wed Mar 28 10:15:37 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-03-29 SPECIAL SEMINAR - Department of Biomedical Engineering Message-ID: <001b01c77111$4488fec0$1b0e4884@estinano> The Department of Biomedical Engineering is pleased to invite you to a special seminar:/ / ** *Prof. Jeffrey J. Fredberg, Ph.D.* Professor of Bioengineering and Physiology Program in Molecular and Integrative Physiological Sciences (MIPS) Department of Environmental Health Harvard School of Public Health Boston, USA *A hard day in the life of a soft cell: * *Physical laws governing cytoskeletal deformation, contraction, and remodeling.* _ _ With every beat of the heart, inflation of the lung, or peristalsis of the gut, cell types of diverse function are subjected to substantial stretch. New data show that cell responses to a transient stretch exhibit remarkable physical similarities to fluidization observed in jammed inert matter, including colloids, pastes, emulsions, and foams, and thus implicate mechanisms mediated not only by specific signaling intermediates, as is usually presumed, but also by nonspecific actions of a slowly evolving network of physical forces. These results support the idea that the cell interior is at once a crowded chemical space and a fragile soft material in which the effects of biochemistry, molecular crowding, and physical forces are complex and inseparable, yet conspire nonetheless to yield remarkably simple phenomenological laws. These laws appear to be universal and thus comprise a striking point of contact between the worlds of cell signaling biology and soft matter physics *Thursday, March 29^th , 2007, at 13:00* Building 59, room 235, Chemical Engineering Seminar Room Ben-Gurion University of the Negev *You are all invited!!!* -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070328/1b19946b/attachment.htm From nano at bgu.ac.il Wed Mar 28 12:30:57 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-11 nanotechnology workshop Message-ID: <00c701c77124$2c1678a0$1b0e4884@estinano> Nanotechnology workshop, Wednesday April 11, 12:00 building 29, room 306,Chemistry Department seminar room Title : Collective dynamics of molecular motors in liquid membranes Speaker: Dr. Yariv Kafri Department of Physics Technion Abstract: The collective dynamics of N weakly coupled molecular motors are considered theoretically. We show, using a discrete lattice model, that the velocity-force curves strongly depend on the effective dynamic interactions between motors and differ significantly from a simple mean field prediction. They become essentially independent of N if it is large enough. For strongly biased motors such as kinesin this occurs if N > 5. The study of a two-state model shows that the existence of internal states can induce effective interactions. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070328/051291ca/attachment.htm From gideonc at bgu.ac.il Mon Apr 9 20:06:22 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-12 Physics Colloquium Message-ID: <200704091706.UAA90002948@tzin.bgu.ac.il> Physics Colloquium DATE: 12-04-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Scanning Probe Microscope-based approaches to nano-biochips SPEAKER: Dr. Levi Gheber, Dept. of Biotechnology Engineering, Ben-Gurion University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Geber.html Refreshments are served at 3:20pm From band at bgu.ac.il Tue Apr 10 19:23:44 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-18 Physical Chemistry Seminar Message-ID: <200704101623.TAA90238972@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 18-04-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Quantum dynamics of nonlinear oscillators SPEAKER: Dr. Omri Gat, Hebrew University of Jerusalem ABSTRACT/COMMENTS: I will introduce the concept of the quasi-flow in order to study the dynamics of the nonlinear oscillator in the semiclassical regime. The quasi-flow is a dynamical mapping of the classical phase plane that represents the time-evolution of the quantum observables and reduces to the classical flow. The quasi-flow is calculated in a semiclassical expansion that reveals the deformation of the classical flow by the quantum nonlinearity. The breakdown of the classical trajectories under the quantum nonlinear dynamics is quantified by the mismatch of the quasi-flow carried by different observables, which can give rise to a dynamical violation of Bell’s inequalities. From Ibar at bgu.ac.il Wed Apr 11 08:11:13 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-17 Lasers Seminar Message-ID: <008601c77bf7$d348ca50$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 17-04-2007 TIME: 3:30pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: Thermodynamics of light-matter interactions SPEAKER: Mr. Erez Boukobza, Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot ABSTRACT/COMMENTS: Thermodynamics of a three-level laser was studied in the pioneering work of Scovil and Schulz-DuBois [Phys. Rev. Lett. 2, 262 (1959)]. In this work we consider the same three-level model, and give a full thermodynamic analysis both in the semiclassical and fully quantum regimes. In the semiclassical regime, we apply a modified version of Alicki?s definitions for heat flux and power, and obtain Carnot's efficiency inequality in differential form when the three-level system is operated as a heat engine (amplifier). Moreover, we derive analytic expressions for thermodynamic fluxes at steady state and obtain Scovil and Schulz-DuBois's laser efficiency formula. By changing the relative degree of excitation in the reservoirs we show that the three-level system has two other modes of operation --- a refrigerator mode and a squanderer mode --- both of which attenuate the electric field. In the fully quantum regime, we analyze an extended (three-level) dissipative Jaynes-Cummings model (ED-JCM) within the framework of a quantum heat engine, using novel formulas for heat flux and power in bipartite systems. We discuss both the dynamical and thermodynamical features of the model. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070411/84c8cbb6/attachment.htm From physics at bgu.ac.il Wed Apr 11 08:27:38 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-11 Astrophysics and Cosmology Seminar Message-ID: <200704110527.IAA91072615@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 11-04-2007 TIME: 12:00 noon (Wed) PLACE: Physics club (Building 29, room 002) TITLE: Analysis of the thermal emission component in Gamma-Ray Bursts SPEAKER: Dr. Asaf Pe\'er, University of Amsterdam ABSTRACT/COMMENTS: This talk is divided into 3 parts. In the first part I will show that there are increasing evidence for a thermal emission component that accompanies the first seconds of the (overall non-thermal) prompt emission phase in GRBs. The temperature and flux of this thermal component show a characteristic temporal behavior for many different bursts. At the first few seconds the temperature is nearly constant, afterward it decays as a power law in time with power law index ~0.8. The ratio of the thermal Flux to the Temperature^4, increases as a power law in time with power law index ~0.6-1.4. In the second part, I will show that the temporal behavior can be understood as an extended emission from the source, taking into account the high latitude emission effect. Finally, I will show that this interpretation allows a direct measurement of two of the least constrained parameters: the bulk motion Lorentz factor \\eta, and the size at the base of the flow. This measurement is insensitive to the inherent uncertainties of previous estimates of \\eta. I will present a specific example: for GRB970828 at z=0.96, \\eta = 305+- 28, and r0 = (3.3+-2.1)*10^8 cm. From nano at bgu.ac.il Wed Apr 11 09:49:33 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-11 nanotechnology workshop- reminder Message-ID: <004501c77c05$90284f30$1b0e4884@estinano> ----- Original Message ----- From: Nano To: nano Sent: Wednesday, March 28, 2007 1:30 PM Subject: 2007-04-11 nanotechnology workshop Nanotechnology workshop, Wednesday April 11, 12:00 building 29, room 306,Chemistry Department seminar room Title : Collective dynamics of molecular motors in liquid membranes Speaker: Dr. Yariv Kafri Department of Physics Technion Abstract: The collective dynamics of N weakly coupled molecular motors are considered theoretically. We show, using a discrete lattice model, that the velocity-force curves strongly depend on the effective dynamic interactions between motors and differ significantly from a simple mean field prediction. They become essentially independent of N if it is large enough. For strongly biased motors such as kinesin this occurs if N > 5. The study of a two-state model shows that the existence of internal states can induce effective interactions. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070411/2ac58105/attachment.htm From jung at bgu.ac.il Wed Apr 11 10:01:45 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-16 Condensed Matter Seminar Message-ID: <200704110701.KAA91419050@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 16-04-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Physics of a Josephson junction and a search for its optimal configuration (experimental data for Nb-Al-AlOx-Nb junctions from a theoretical viewpoint) SPEAKER: Mikhail Belogolovskii, Donetsk Physical & Technical Institute, National Academy of Sciences of Ukraine ABSTRACT/COMMENTS: OUTLINE: 1. Main requirements for the applications 2. Main types of Josephson heterostructures: their advantages and shortcomings 3. SNIS junctions, their advantages and shortcomings 4. Experimental data for Nb-Al-AlOx-Nb junctions from a theoretical viewpoint 5. Conclusions From nano at bgu.ac.il Wed Apr 11 14:01:52 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-18 nanotechnology workshop Message-ID: <00c501c77c28$cf871120$1b0e4884@estinano> Nanotechnology workshop, Wednesday April 18, 12:00 building 29, room 306,Chemistry Department seminar room Title : Dynamics of septum formation in E. coli Speaker: Prof. Mario Feingold Department of Physics BGU Abstract: We use single cell phase-contrast and fluorescence time-lapse microscopy to monitor the morphological changes during the division of E. coli. To bypass the limitations of optical resolution, we process the images using pixel intensity values for edge detection. We study the dynamics of the constriction width, W, and find that its formation starts shortly after birth much earlier than can be detected by simply viewing phase-contrast images. A simple geometrical model is shown to reproduce the behavior of W(t). Moreover, the time-dependence of the cell length, L(t), consists of three linear regimes. The growth rates in the different regimes are related to each other and to the parameters of our model. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070411/cfa8435d/attachment.htm From band at bgu.ac.il Sun Apr 15 09:52:13 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-25 Physical Chemistry Seminar Message-ID: <200704150652.JAA93932990@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 25-04-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Hybrid Metal-Semiconductor Nanoparticles SPEAKER: Professor Uri Banin, The Hebrew University of Jerusalem ABSTRACT/COMMENTS: An important frontier in nano-materials research concerns nanoparticles with different materials in the same nanostructure as means of increasing functionality. One particularly interesting combination of materials is that of a metal and semiconductor in the same nanoparticle where metal tips can provide anchor points for electrical connections and for self assembly. We developed the growth of metal (Au) tips on the apexes of semiconductor (CdSe) rods, forming \'nano-dumbbells\' (NDB\'s), via a simple chemical reaction . From the viewpoint of self-assembly they are equivalent to bi-functional molecules such as the di-thiols manifesting two sided chemical connectivity and the use of the tips for assembly with biomolecular linking is demonstrated. We also found that by increasing the concentration of gold in the reaction, rods with a metal tip on one side are formed. This occurs by a unique electrochemical ripening mechanism as substantiated by experimental work and model calculations. Such systems manifest a unique model for a metal-semiconductor nanoscale junction. A fundamental and intriguing problem associated with such systems is the optical and electronic properties of the metal-SC nanojunctions. The electronic properties of metal-semiconductor nanojunctions were investigated by several methods including scanning tunneling spectroscopy of the gold-tipped CdSe rods and by electrostatic force. References: T. Mokari, E. Rothenberg, I. Popov, U. Banin, Science 304, 1787 (2004). A. Salant, E. Amitai-Sadovsky, U. Banin, J. Am. Chem. Soc. 128, 10006 (2006). T. Mokari, C. G. Sztrum, A. Salant, E. Rabani, U. Banin, Nature Materials 4, 855 (2005). D. Steiner, T. Mokari, U. Banin, O. Millo, Phys. Rev. Lett. 95, 056805 (2005). From physics at bgu.ac.il Sun Apr 15 10:53:31 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-18 Physical Chemistry Seminar Message-ID: <200704150753.KAA94760730@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 18-04-2007 TIME: 16:00 PLACE: Ben-Gurion University of the Negev TITLE: \"Quantum dynamics of nonlinear oscillators\" SPEAKER: Professor Omri Gat, ABSTRACT/COMMENTS: Abstract: I will introduce the concept of the quasi-flow in order to study the dynamics of the nonlinear oscillator in the semiclassical regime. The quasi-flow is a dynamical mapping of the classical phase plane that represents the time-evolution of the quantum observables and reduces to the classical flow. The quasi-flow is calculated in a semiclassical expansion that reveals the deformation of the classical flow by the quantum nonlinearity. The breakdown of the classical trajectories under the quantum nonlinear dynamics is quantified by the mismatch of the quasi-flow carried by different observables, which can give rise to a dynamical violation of Bell’s inequalities. From gideonc at bgu.ac.il Sun Apr 15 13:10:39 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-19 Physics Colloquium Message-ID: <200704151010.NAA94792369@tzin.bgu.ac.il> Physics Colloquium DATE: 19-04-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Bell\'s Theorem - a critical review SPEAKER: Dr. Nathan Argaman, NRC-Negev ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Argaman.html Refreshments are served at 3:20pm From nano at bgu.ac.il Mon Apr 16 10:04:53 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-18 nanotechnology workshop -correction Message-ID: <001101c77ff5$88adb8f0$1b0e4884@estinano> Nanotechnology workshop, Wednesday April 18, 12:00 building 29, room 306,Chemistry Department seminar room Title : Chemical Solution Deposition of Nano-Structured PZT Films Speaker: Dr. Aleksey Etin Chemical Engineering Department Technion Abstract: PZT (PbZrxTi1-xO3) films are becoming increasingly important due to their vast applications in Micro-Electro-Mechanical-Systems (MEMS) as sensors and actuators as well as in non-volatile FeRAM (Ferroelectric Random Access Memory)?. Chemical Solution Deposition (CSD) evolved as the optimal method for preparation of high quality ceramic films since it allows simple and fast processing at low temperatures and large coating area. The main obstacles that limit the utilization of the CSD method are the non-uniformity of the film composition and coating thickness on the nano- and macro-scale, respectively. The deviations from stoichiometry during processing, lead to formation of secondary phases and degradation of the piezo- and ferroelectric properties. At the same time the macro-defects are intolerable since they decrease yield of the devices and process reliability. We have found that the film properties can be effectively controlled by the precursor chemistry and composition. The nano-scale uniformity is governed by the chemical structure of the precursor while the macro-scale quality depends on its wetting, surface tension as well as reactivity. The mechanisms of the nano- and macro- heterogeneities formation and means to avoid them will be discussed. The method we developed for deposition of high quality, uniform PZT films on 4 inch wafers and application of these films will be demonstrated. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070416/da601c5e/attachment.htm From physics at bgu.ac.il Tue Apr 17 10:40:57 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-05-01 Particles and Fields Seminar Message-ID: <200704170740.KAA740693@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 01-05-2007 TIME: 17:00 PLACE: Physics club (Building 29, room 002) TITLE: \"On Heavy Ion Collisions: From Navier-Stokes Equation to AdS Black Holes and back again\" SPEAKER: Michael Lublinsky , ABSTRACT/COMMENTS: It was realized recently that Quark Gluon Plasma produced at RHIC is in fact strongly coupled and well described by almost ideal relativistic hydrodynamics. Remarkably, strongly coupled plasmas can be alternatively studied using models inspired by the AdS/CFT duality. We use these models to estimate entropy production during the hydro phase at RHIC. From physics at bgu.ac.il Tue Apr 17 10:50:08 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-18 Organic/Biophysics Chemistry Seminar Message-ID: <200704170750.KAA745187@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar DATE: 18-04-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Seminar Room) TITLE: \"Internal Chloride Displacement in Hexacoordinate Silicon Dichelates: Mixed-Chelate Formation by Replacement of N®Si to O®Si Coordination\" (Yakubovich) \"Unexpected Different Reactivities of Pentacoordinate Silicon Dichelates with Acyclic and Cyclic Alkylideneimino Ligands\" (Sharabi) SPEAKER: Shiri Yakubovich, Meital Sharabi, Department of Chemistry, Ben-Gurion University ABSTRACT/COMMENTS: שימו לב- בסמינר זה יינתנו שתי הרצאות From physics at bgu.ac.il Tue Apr 17 11:01:21 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-26 Physics Colloquium Message-ID: <200704170801.LAA762176@tzin.bgu.ac.il> Physics Colloquium DATE: 26-04-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Semiconductor quantum dots as entangled light sources SPEAKER: David Gershoni , Department of Physics , Technion ABSTRACT/COMMENTS: Entangled photon pairs are emitted from a biexciton decay cascade of single quantum dots when spectral filtering is applied. We show this by experimentally measuring the density matrix of the polarization state of the photon pair emitted from a continuously pumped quantum dot. The matrix clearly satisfies the Peres criterion for entanglement. By applying in addition a temporal window, the quantum dot becomes an entangled light source. Refreshments are served at 3:20pm From physics at bgu.ac.il Tue Apr 17 12:43:21 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-05-01 Particles and Fields Seminar - Correction! Message-ID: <200704170943.MAA795632@tzin.bgu.ac.il> Particles and Fields Seminar - Correction! DATE: 01-05-2007 TIME: 17:00 PLACE: Physics club (Building 29, room 002) TITLE: \"On Heavy Ion Collisions: From Navier-Stokes Equation to AdS Black Holes and back again\" SPEAKER: Dr. Michael Lublinsky , State University of New York, Stony Brook, NY ABSTRACT/COMMENTS: It was realized recently that Quark Gluon Plasma produced at RHIC is in fact strongly coupled and well described by almost ideal relativistic hydrodynamics. Remarkably, strongly coupled plasmas can be alternatively studied using models inspired by the AdS/CFT duality. We use these models to estimate entropy production during the hydro phase at RHIC. From physics at bgu.ac.il Tue Apr 17 12:44:32 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-05-01 Particles and Fields Seminar - Correction! Message-ID: <200704170944.MAA813482@tzin.bgu.ac.il> Particles and Fields Seminar - Correction! DATE: 01-05-2007 TIME: 17:00 PLACE: Physics club (Building 29, room 002) TITLE: \"On Heavy Ion Collisions: From Navier-Stokes Equation to AdS Black Holes and back again\" SPEAKER: Dr. Michael Lublinsky , State University of New York, Stony Brook, NY ABSTRACT/COMMENTS: It was realized recently that Quark Gluon Plasma produced at RHIC is in fact strongly coupled and well described by almost ideal relativistic hydrodynamics. Remarkably, strongly coupled plasmas can be alternatively studied using models inspired by the AdS/CFT duality. We use these models to estimate entropy production during the hydro phase at RHIC. From physics at bgu.ac.il Wed Apr 18 10:21:52 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-25 Astrophysics and Cosmology Seminar Message-ID: <200704180721.KAA1540509@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 25-04-2007 TIME: 12:00 noon (Wed) PLACE: Physics club (Building 29, room 002) TITLE: Unexpected features of Gravitational Trapping by Domain Walls SPEAKER: Idan Shilon, Physics Department, Ben Gurion University ABSTRACT/COMMENTS: From nano at bgu.ac.il Wed Apr 18 15:23:03 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-25 nanotechnology workshop Message-ID: <00f101c781b4$4fbe33b0$1b0e4884@estinano> Nanotechnology workshop, Wednesday April 25, 12:00 building 29, room 306,Chemistry Department seminar room Title : Fullerenes for and with Solar Energy Speaker: Dr. Ivgenny Katz Dept. of Solar Energy and Environmental Physics, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070418/96732e33/attachment.htm From physics at bgu.ac.il Sun Apr 22 10:46:20 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:25 2009 Subject: [Phys-seminars] 2007-04-25 Physical Chemistry Seminar Message-ID: <200704220746.KAA4935473@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 25-04-2007 TIME: 16:00 PLACE: Bldg. 29, Room 306 (Seminar Room) TITLE: \"Hybrid Metal-Semiconductor Nanoparticles\" SPEAKER: Professor Uri Banin, ABSTRACT/COMMENTS: An important frontier in nano-materials research concerns nanoparticles with different materials in the same nanostructure as means of increasing functionality. One particularly interesting combination of materials is that of a metal and semiconductor in the same nanoparticle where metal tips can provide anchor points for electrical connections and for self assembly. We developed the growth of metal (Au) tips on the apexes of semiconductor (CdSe) rods, forming \'nano-dumbbells\' (NDB\'s), via a simple chemical reaction . From the viewpoint of self-assembly they are equivalent to bi-functional molecules such as the di-thiols manifesting two sided chemical connectivity and the use of the tips for assembly with biomolecular linking is demonstrated. We also found that by increasing the concentration of gold in the reaction, rods with a metal tip on one side are formed. This occurs by a unique electrochemical ripening mechanism as substantiated by experimental work and model calculations. Such systems manifest a unique model for a metal-semiconductor nanoscale junction. A fundamental and intriguing problem associated with such systems is the optical and electronic properties of the metal-SC nanojunctions. The electronic properties of metal-semiconductor nanojunctions were investigated by several methods including scanning tunneling spectroscopy of the gold-tipped CdSe rods and by electrostatic force. References: T. Mokari, E. Rothenberg, I. Popov, U. Banin, Science 304, 1787 (2004). A. Salant, E. Amitai-Sadovsky, U. Banin, J. Am. Chem. Soc. 128, 10006 (2006). T. Mokari, C. G. Sztrum, A. Salant, E. Rabani, U. Banin, Nature Materials 4, 855 (2005). D. Steiner, T. Mokari, U. Banin, O. Millo, Phys. Rev. Lett. 95, 056805 (2005). From Ibar at bgu.ac.il Wed Apr 25 08:36:57 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-01 Lasers Seminar Message-ID: <01cc01c786fb$bda30800$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 01-05-2007 TIME: 3:30pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: NIR ? Monolithic Micro-Chip Lasers SPEAKER: Dr. Ehud Galun, ELOP ? Electro optics Industries Ltd. ABSTRACT/COMMENTS: A new and novel technology has been developed in the last few years enabling building monolithic miniature lasers systems based on combined amplifying crystal, Q switch and mirrors. The advantages of these systems upon a conventional solid state laser where the active parts are assembled to a mechanical bracket consist of: low cost, low weight, miniaturization, good beam quality and high durability. A variety of potential applications for these systems include: LIDARs, Range Finders, Materials Processing and Medical Treatments. We would like to present a monolithic 1W average power, 1.06 micron microchip laser based on Cr:YAG//Nd:YAG crystal. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070425/bbbd500c/attachment.htm From jung at bgu.ac.il Wed Apr 25 10:17:37 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-04-30 Condensed Matter Seminar Message-ID: <200704250717.KAA7318281@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 30-04-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Fluctuations in magnetic systems: from thermal noise to the Barkhausen effect. SPEAKER: Gianfranco Durin - Dozor Fellow, Istituto Nazionale di Ricerca Metrologica (INRIM) (former Istituto Elettrotecnico Nazionale Galileo Ferraris), Torino, Italy ABSTRACT/COMMENTS: We review key experimental and theoretical results on the Barkhausen effect, focusing on the statistical analysis of the noise. We discuss the experimental methods and the material used and review recent measurements. The picture emerging from the experimental data is that Barkhausen avalanche distributions and power spectra can be described by scaling laws as in critical phenomena. In addition, there is growing evidence that soft ferromagnetic bulk materials can be grouped in different classes according to the exponent values. Soft thin films still remain to be fully explored both experimentally and theoretically. Reviewing theories and models proposed in the recent past to account for the scaling properties of the Barkhausen noise, we conclude that the domain wall depinning scenario successfully explains most experimental data. From physics at bgu.ac.il Wed Apr 25 11:07:24 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-02 Astrophysics and Cosmology Seminar Message-ID: <200704250807.LAA7310284@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 02-05-2007 TIME: 12:00 noon (Wed) PLACE: Physics club (Building 29, room 002) TITLE: Isotherms clustering in cosmic microwave background radiation SPEAKER: Alexander Bershadskii, ICAR, Tel Aviv ABSTRACT/COMMENTS: Since the strong clustering of luminous matter in the observable universe is a consequence of an initial non-uniformity of the baryon-photon fluid in the last scattering surface, an investigation of clustering of the isotherms in the cosmic microwave background has been performed. The isotherms clustering has been related to the baryon-photon fluid dynamics and the Taylor-microscale Reynolds number of this motion is estimated to be $10^2$. 3-year WMAP cosmic microwave background map has been used in this investigation. From nano at bgu.ac.il Wed Apr 25 12:04:27 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-02 nanotechnology workshop Message-ID: <008d01c78718$ba0fa1e0$1b0e4884@estinano> Nanotechnology workshop, Wednesday May 2, 12:00 building 29, room 306,Chemistry Department seminar room Title : When Hydrophobes Meet Electrolytes: Insights from Computer Experiments Speaker: Ronen Zangi Columbia University Abstract: Recognition of electrolyte solutions as central to the regulation of chemical and biological processes goes back more than a century, starting with Hofmeister's experiments on the ability of different ions to precipitate proteins. This regulation is a result of modulations in the solvent induced interactions. In this talk we will present results on the ability of different type of salts to modify the strength of the solvent induced interactions between large hydrophobic plates. The results show that amplification of the hydrophobic interaction (salting-out) is a purely entropic effect and is induced by high charge density ions that exhibit preferential exclusion. In contrast, a reduction of the hydrophobic interaction (salting-in) is induced by low charge density ions that exhibit preferential binding, the effect being either entropic or enthalpic. By analyzing changes in the enthalpy and entropy differences upon hydrophobic collapse (in salt solutions relative to pure water) we propose the mechanisms by which salting-in and salting-out take place. In addition, we will present results on changes of the solvent induced interactions between small hydrophobic particles. In this case, we do not observe a monotonic relationship between the degree of preferential binding/exclusion and changes in magnitude of the hydrophobic interaction. In particular, we find that at low salt/cosolute concentrations, salts with low charge density ions increase the solvent mediated attractions by forming a `micelle-like' structure. Our findings are relevant to phenomena long studied in solution chemistry, as we demonstrate the significant, yet subtle, effects of electrolytes on hydrophobic aggregation and collapse. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070425/42e7e96f/attachment.htm From band at bgu.ac.il Thu Apr 26 17:43:35 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-02 Physical Chemistry Seminar Message-ID: <200704261443.RAA8404453@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 02-05-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Charge Transfer Processes of Atmospheric Molecules in Water Clusters SPEAKER: Dr. Yifat Miller, The Hebrew University of Jerusalem ABSTRACT/COMMENTS: Molecular Dynamics simulations, carried out “on the fly” for potentials from electronic structure calculations are reported for several thermal and photochemical processes of molecules in water and other clusters. For the relatively small clusters, the reliable MP2 ab initio method is used, while for larger clusters most simulations employ the semi-empirical PM3, modified for a more realistic description of some of the processes. The simulations provide insights into the mechanisms, rates and yields of the processes, and are suggestive as to their potential importance in atmospheric conditions. The processes studied include: (a) Overtone induced reactions of HONO and at interfaces. It is concluded that for surfaces that bind strongly to the molecule (e.g. H_{2}O on HNO_{3}) the chemical reaction is suppressed, but for the cases of weak binding (HONO on H_{2}O), photochemistry is predicted to take place. (b) The neutralization of H^{+} and NO_{3}^{-} is found to take place on sub-picosecond timescales in small clusters. HNO3 is found to be a weak acid in these systems. (c) Hydrolysis of N_{2}O_{4} at water clusters is studied, and the result supports the mechanism proposed by Finlayson-Pitts and coworkers, in particular a step involving dissociation of an isomer of N_{2}O_{4} into ions. From physics at bgu.ac.il Sun Apr 29 10:51:11 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-03 Physics Colloquium Message-ID: <200704290751.KAA10706293@tzin.bgu.ac.il> Physics Colloquium DATE: 03-05-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Colloquium schedule 2006/7 SPEAKER: , ABSTRACT/COMMENTS: Refreshments are served at 3:20pm Mechanical forces acting externally on entire tissues, or generated internally by the contractile activity of individual cells within a tissue, play an important regulatory role in many physiological processes, including: bone and muscle growth and wound healing. Understanding the response of single cells in artificial substrates to mechanical loadings, and their behavior as a collective, is important not only for basic biological science but also for the rational design of artificial tissues. Individual cells possess specific mechanisms that enable them to sense and respond to changes in their mechanical environment. By pulling on their environment cells sense rigidity gradients, boundaries and strain. Many cell types respond to these signals by actively adjusting cell polarity. On a macroscopic level, the forces generated by a collection of cells in a tissue significantly alter the overall elastic response of the system. We predict the response of cells in a three dimensional elastic medium to externally applied strain fields. The cells are modeled as polarizable elastic force dipoles that can change their orientation in response to the local elastic stress. We model the ensemble of cells by an extension of the treatment of dielectric response of polar molecules. We introduce the elastic analogy of the frequency-dependant dielectric function of the medium that allows us to predict the average cell polarization and orientational order, the effective material constants, and the dynamical response to time-varying cyclic loadings. From physics at bgu.ac.il Sun Apr 29 14:03:46 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-02 Physical Chemistry Seminar Message-ID: <200704291103.OAA10829024@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 02-05-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Charge Transfer Processes of Atmospheric Molecules in Water Clusters SPEAKER: Dr. Yifat Miller, The Hebrew University of Jerusalem, ABSTRACT/COMMENTS: Molecular Dynamics simulations, carried out “on the fly” for potentials from electronic structure calculations are reported for several thermal and photochemical processes of molecules in water and other clusters. For the relatively small clusters, the reliable MP2 ab initio method is used, while for larger clusters most simulations employ the semi-empirical PM3, modified for a more realistic description of some of the processes. The simulations provide insights into the mechanisms, rates and yields of the processes, and are suggestive as to their potential importance in atmospheric conditions. The processes studied include: (a) Overtone induced reactions of HONO and at interfaces. It is concluded that for surfaces that bind strongly to the molecule (e.g. H_{2}O on HNO_{3}) the chemical reaction is suppressed, but for the cases of weak binding (HONO on H_{2}O), photochemistry is predicted to take place. (b) The neutralization of H^{+} and NO_{3}^{-} is found to take place on sub-picosecond timescales in small clusters. HNO3 is found to be a weak acid in these systems. (c) Hydrolysis of N_{2}O_{4} at water clusters is studied, and the result supports the mechanism proposed by Finlayson-Pitts and coworkers, in particular a step involving dissociation of an isomer of N_{2}O_{4} into ions. From gideonc at bgu.ac.il Sun Apr 29 22:22:06 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-03 Physics Colloquium Message-ID: <200704291922.WAA11205765@tzin.bgu.ac.il> Physics Colloquium DATE: 03-05-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Prof. Ramy Brustein SPEAKER: Quantum Black Holes Challenge Basic Principles of Quantum Mechanics , Dept. of Physics, Ben-Gurion University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Brustein.html Refreshments are served at 3:20pm From physics at bgu.ac.il Mon Apr 30 10:55:16 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-02 Organic/Biophysics Chemistry Seminar1 Message-ID: <200704300755.KAA11576759@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar1 DATE: 02-05-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"The investigation of major steps leading to significant enhancement of ciliary beat frequency in large mammalians\" SPEAKER: Elena Passwell (Itkin), Department of Chemistry, Ben-Gurion University ABSTRACT/COMMENTS: The mucociliary system is responsible for clearing inhaled particles and pathogens from the airways. Highly cooperative beating of cilia at high frequencies enables the mucociliary system to carry relatively large objects, at remarkable velocity. This work elucidates the role of intracellular pH (pHi) and Ca2+ in regulation of ciliary beat frequency (CBF). From physics at bgu.ac.il Mon Apr 30 10:56:49 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-02 Organic/Biophysics Chemistry Seminar2 Message-ID: <200704300756.KAA11578193@tzin.bgu.ac.il> Organic/Biophysics Chemistry Seminar2 DATE: 02-05-2007 TIME: 18:00 PLACE: Bldg. 29 Room 306 (Chemistry Seminar Room) TITLE: \"The search for new specific and efficient tryptophanase inhibitors\" SPEAKER: Liraz Shidlovsky, Department of Chemistry, Ben-Gurion University ABSTRACT/COMMENTS: Tryptophanase (tryptophan indole-lyase, Trpase, EC 4.1.99.1) is a widely distributed bacterial pyridoxal 5\'-phosphate (PLP)-dependent enzyme that catalyses α,β-elimination and β-replacement reactions of L-Trp and a number of other β-substituted amino acids. Trpase consists of four identical 52 kDa subunits; each binds one molecule of PLP, which forms an aldimine bond with a lysine residue. The enzymatic reaction with Trp results in pyruvate, ammonia and indole production. It was suggested that indole is a cell-cell communications and signaling molecule, essential for bacteria multiplication and biofilm formation at the site of infection. Biofilms destroy equipment and food, contaminate water, and are the cause of many types of illnesses associated with pathogenic organisms (e.g., otitis media, bacterial endocarditis, cystic fibrosis and Legionnaire\'s disease). X-ray crystallography and the known mechanism of Trpase enzymatic activity provided the informa tion necessary for the design and synthesis of active-site-specific inhibitors. Most synthesized quasi-substrates showed Trpase inhibition at a milimolar range. Finding an effective inhibitor of Trpase will reduce indole production. Since Trpase is a bacterial enzyme with no counterpart in eukaryotic cells, this inhibitor may eliminate biofilm formation, providing a new generation of antibiotics. From jung at bgu.ac.il Tue May 1 09:22:19 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-07 Condensed Matter Seminar Message-ID: <200705010622.JAA11735919@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 07-05-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: No seminar this weak. You are invited to participate in ISF Workshop on Superconductivity and Magnetism in Kefar Hamaccabiach. For program and registration visit: http://www.isf-minerva-07.biu.ac.il/index.php SPEAKER: , ABSTRACT/COMMENTS: From gideonc at bgu.ac.il Tue May 1 12:32:53 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-03 Physics Colloquium Message-ID: <200705010932.MAA12450784@tzin.bgu.ac.il> Physics Colloquium DATE: 03-05-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Quantum Black Holes Challenge Basic Principles of Quantum Mechanics SPEAKER: Prof. Ramy Brustein, Dept. of Physics, Ben-Gurion University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Brustein.html Refreshments are served at 3:20pm From Ibar at bgu.ac.il Wed May 2 08:14:33 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-08 Lasers Seminar Message-ID: <073a01c78c78$c4f652b0$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 08-05-2007 TIME: 3:30pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: Fiber Bragg gratings and tailored Brillouin scattering processes in fibers SPEAKER: Mr. Avi Zadok, Faculty of Engineering, Tel-Aviv University ABSTRACT/COMMENTS: Fiber Bragg Gratings (FBG's) are fiber-optic components in which the refractive index of the core is periodically modulated. The index modulation leads to distributed scattering of incoming optical fields along the length of the grating. With proper matching of the index modulation period and the wavelength of the incoming signal, constructive coupling into the counter-propagating mode of the fiber (reflection mode), or into cladding and radiative modes (transmission mode), can be achieved. With careful tailoring of the index modulation depth and period along the grating, the spectral dependence of FBG's reflection and transmission may be synthesized. Over the last three decades, FBG's had found a variety of applications in optical communications and fiber-optic sensors. In optical communications, FBG'sbased WDM channel-selection filters, gain equalizers and chromatic dispersion compensators are all commercially available. In the field of optical sensing, FBG's are incorporated into smart structures for ultra-sensitive strain measurements, and positioned along fiber links for distributed temperature detection. Recently, non-linear propagation of pulses along FBG's is also being considered. Standard FBG's are mostly fixed structures, in which the index modulation is permanently imprinted. However, a temporary, traveling acoustic grating may be optically introduced in the fiber through the non-linear mechanism of Stimulated Brillouin Scattering (SBS). In SBS, two counter-propagating optical waves, a strong pump and a weak probe, combine to form an acoustic grating via opto-mechanical electrostriction. The acoustic grating, in turn, scatters power from the pump into the probe, yielding a distributed amplifier that is highly frequency selective. Recently, SBS amplification had drawn much attention, as an underlying basis for "slow light" implementations in fibers. In these setups, the group delay of broadband probe pulses is controllable, with considerable implications to optical data synchronization and microwave photonics processing in radar systems. References: 1. R. Kashyap, Fiber Bragg Gratings, Academic Press, San Diego, CA (1999) 2. T. A. Strasser, and T. Erdogan, "Fiber-grating devices in high performance optical communications systems," in Optical Fiber Communications IVA, I. Kaminow and T. Li ed., Academic Press, San Diego, CA (2002) 3. R. W. Boyd, and D. J. Gauthier, ?Slow and fast light,? in Progress in Optics, E. Wolf, ed. (Elsevier, Amsterdam, 2002), Vol. 43 pp. 497-530. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070502/883b9908/attachment.htm From nano at bgu.ac.il Wed May 2 12:09:34 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-09 nanotechnology workshop Message-ID: <006701c78c99$9ab8b670$1b0e4884@estinano> Nanotechnology workshop, Wednesday May 9, 12:00 building 29, room 306,Chemistry Department seminar room Title : Molecular-and bio-based electrical DevicesSpeaker: Shahar Richter Chemistry Department Tel Aviv University -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070502/95b6e426/attachment.htm From gideonc at bgu.ac.il Sat May 5 15:52:45 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-10 Physics Colloquium Message-ID: <200705051252.PAA15921916@tzin.bgu.ac.il> Physics Colloquium DATE: 10-05-2007 TIME: 3:30pm (Thu) PLACE: High Tech building 37, Auditorium 202 TITLE: Experiments with Ultracold Helium Atoms SPEAKER: Prof. Claude Cohen-Tannoudji, College de France and Laboratoire Kastler Brossel Ecole Normale Superieure, Paris, France ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Tannoudji.html Refreshments are served at 3:20pm From dcohen at bgu.ac.il Tue May 8 09:06:28 2007 From: dcohen at bgu.ac.il (Doron Cohen) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-13 Special Condensed Matter DIP Session Message-ID: Special Condensed Matter DIP Session DATE: 13-05-2007 TIME: 14:30-16:00 Sunday PLACE: The NEW seminar room in the NEW physics building (near the bridge, 2nd floor) REMARKS: This open session is part of a DIP meeting titled "Dynamics of Electrons and Collective Modes in Nanostructures" We start the session SHARP at 14:30 so as not to be in conflict with the 16:30 Dean's Podium. PROGRAM: * 14:30 Ora Entin-Wohlman (Ben Gurion University) "AC spin-Hall effect in insulators" * 15:15 Felix von Oppen (Freie Univesitaet Berlin) "Vibrational absorption sidebands in single-molecule transistors" From physics at bgu.ac.il Tue May 8 09:31:11 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-13 Special Condensed Matter DIP Session Message-ID: <200705080631.JAA17628528@tzin.bgu.ac.il> Special Condensed Matter DIP Session DATE: 13-05-2007 TIME: 14:30-16:00 PLACE: The NEW seminar room in the Bldg.54 Room 207 TITLE: \"Dynamics of Electrons and Collective Modes in Nanostructures\" SPEAKER: , Ora Entin-Wohlman (Ben Gurion University) Felix von Oppen (Freie Univesitaet Berlin) ABSTRACT/COMMENTS: PROGRAM: * 14:30 Ora Entin-Wohlman (Ben Gurion University) \"AC spin-Hall effect in insulators\" * 15:15 Felix von Oppen (Freie Univesitaet Berlin) \"Vibrational absorption sidebands in single-molecule transistors\" From physics at bgu.ac.il Tue May 8 11:01:19 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-13 Special Condensed Matter DIP Session Message-ID: <200705080801.LAA18271818@tzin.bgu.ac.il> Special Condensed Matter DIP Session DATE: 13-05-2007 TIME: 14:30-16:00 PLACE: NEW seminar room, 207. Bldg.54 TITLE: \"Dynamics of Electrons and Collective Modes in Nanostructures\" SPEAKER: , Ora Entin-Wohlman (Ben Gurion University) Felix von Oppen (Freie Univesitaet Berlin) ABSTRACT/COMMENTS: PROGRAM: * 14:30 Ora Entin-Wohlman (Ben Gurion University) \"AC spin-Hall effect in insulators\" * 15:15 Felix von Oppen (Freie Univesitaet Berlin) \"Vibrational absorption sidebands in single-molecule transistors\" We start the session SHARP at 14:30 so as not to be in conflict with the 16:30 Dean\'s Podium. From physics at bgu.ac.il Tue May 8 14:25:48 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-09 astrophysics seminar Message-ID: <200705081125.OAA18395075@tzin.bgu.ac.il> astrophysics seminar DATE: 09-05-2007 TIME: 12-00 PLACE: physics club TITLE: Annihilation of alternating magnetic fields at the relativistic shock. SPEAKER: Yuri Lyubarsky, ABSTRACT/COMMENTS: From Ibar at bgu.ac.il Wed May 9 08:05:42 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-15 Lasers Seminar Message-ID: <01da01c791f7$b1ac30b0$d10f4884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 15-05-2007 TIME: 3:30pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: Beam-quality-enhancement in multi-kW rod-based lasers by use of radially-polarized light and phase-front correction SPEAKER: Dr. Inon Moshe, Electro-Optics Div., Soreq NRC, Yavne 81800, Israel ABSTRACT/COMMENTS: High-power rod-based solid-state lasers have been widely-used for many years. Switching from flashlamp to diode pumping resulted in a jump in beam-quality, but performance was still modest. M^2 values of 70-100 were achieved. Our work in Soreq NRC demonstrates a further dramatic improvement in the beam quality of multi-KW CW Nd:YAG lasers by use of radial-polarization and aberration compensation. To date, we have achieved M^2 on the order of 10, and the road-map for achieving M^2~2 is clear. Rod based lasers have the advantage of simplicity. Unfortunately, rods suffer from thermal effects that degrade beam quality as power is scaled-up. The main beam quality degradation factors are thermally induced bifocusing and spherical aberration (SA). Non-radially-symmetric pump distributions cause non-radially-symmetric optical aberrations. For unpolarized or linearly polarized beams, bifocusing is the worst beam quality degradation factor. We bypass this aberration by using radially or azimuthally polarized beams, as these polarizations interact with just one bifocal-lens axis. Thermal SA in laser rods has a positive sign opposite to the negative SA of convex spherical lenses. We exploit this fact to produce a SA compensator based on two plano-convex positive lenses in a relay-imaging telescope. Non-radially symmetric aberrations are compensated using two rotated pump-chambers. We applied these compensation techniques in a Master-Oscillator-Power-Amplifier laser. A radially polarized beam was generated in an oscillator and was amplified in an amplifier chain. Main laser-beam power was achieved through a Soreq manufactured 2KW amplifiers. Output beam power was >2KW with M^2<10 (beam-parameter-product < 3.3mm?mrad). Light-light efficiency of the last amplifier was about 30%. Improvements to this system are, now, focused on a new pump chamber design with an excellent radially symmetric pump distribution together with application of higher order aberration correction elements. Preliminary results are encouraging, indicating that higher powers and better M^2 can be achieved with rod based lasers. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070509/b9f54176/attachment.htm From nano at bgu.ac.il Wed May 9 12:37:17 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-16 nanotechnology workshop Message-ID: <00ae01c7921d$a210b7e0$1b0e4884@estinano> Nanotechnology workshop, Wednesday May 16, 12:00 building 29, room 306,Chemistry Department seminar room Title : Photoelectron Spectroscopy as a Tool to Investigate Chemical Bond: Synthesis, Characterization and Properties of Molecular Monolayers Covalently Assembled on SiO2 and Si(100) Substrates Speaker:Antonino Gulino Chemistry Department Universit? di Catania, Italy Abstract: Monolayer chemistry and surface engineering represent a fast emerging field. In particular the assembly of new molecular-based materials, is of much relevance for the design and formation of nanodevices, including memory elements, sensors, optical switches, and logic architectures. Moreover, there is much current academic, industrial and strategic interest in the synthesis of hybrid inorganic/organic nanomaterials by covalent bonding of organic molecules on suitable inorganic surfaces in the perspective of fabrication of devices able to recognize parts per million (ppm-levels) of chemicals. The combination of sensor chemistry and surface engineering allow the easy fabrication of inexpensive, miniature, and robust sensing materials. Porphyrins, fullerenes, phthalocyanines and other metal complexes are suitable candidates as molecular building blocks for the formation of monolayer-based memory, switch and sensor elements by virtue of their dominating optical properties. In this context, here we propose paths suited to anchor on both transparent fused silica substrates and on Si(100) porphyrin and fullerene molecules that, in turn, grant molecular recognition properties to the final systems. Molecular monolayer characterization has been carried out with X-ray photoelectron spectroscopy. This technique is ideal since allows high vertical resolution and gives information on the bonding states of the grafted molecules by the analysis of angle-resolved measurements. These measurements provide unique chemical information not available with many other spectroscopic techniques. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070509/db18abd1/attachment.htm From gideonc at bgu.ac.il Wed May 9 14:06:52 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-10 Colloquium reminder - Notice the change of room Message-ID: <200705091106.OAA19276455@tzin.bgu.ac.il> Colloquium reminder - Notice the change of room DATE: 10-05-2007 TIME: 3:30pm (Thu) PLACE: High Tech building 37, Auditorium 202 TITLE: Experiments with Ultracold Helium Atoms SPEAKER: Prof. Claude Cohen-Tannoudji, College de France and Laboratoire Kastler Brossel Ecole Normale Superieure, Paris, France ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Tannoudji.html Refreshments are served at 3:20pm From gideonc at bgu.ac.il Wed May 9 14:07:30 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-10 Colloquium - Notice the change of room Message-ID: <200705091107.OAA19248845@tzin.bgu.ac.il> Colloquium - Notice the change of room DATE: 10-05-2007 TIME: 3:30pm (Thu) PLACE: High Tech building 37, Auditorium 202 TITLE: Experiments with Ultracold Helium Atoms SPEAKER: Prof. Claude Cohen-Tannoudji, College de France and Laboratoire Kastler Brossel Ecole Normale Superieure, Paris, France ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Tannoudji.html Refreshments are served at 3:20pm From jung at bgu.ac.il Thu May 10 14:54:07 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-14 Condensed Matter Seminar Message-ID: <200705101154.OAA20044414@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 14-05-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Sharp Superconductor-Insulator Transition in Short Wires SPEAKER: Yuval Oreg, Faculty of Physics, Weizmann Institute of Science ABSTRACT/COMMENTS: Recent experiments on short MoGe nanowires show a sharp superconducting-insulating transition at the universal resistance RQ=h/(4e2), contrary to the expectation of a smooth temperature dependence of the resistance for such Josephson-like systems. We present a self-consistent renormalization-group treatment of interacting quantum phase slips in short superconducting wires, which reproduces this sharp universal transition. Our method should also apply to other systems in the sine-Gordon universality class, in the previously inaccessible intermediate-coupling regime. From physics at bgu.ac.il Sun May 13 10:41:16 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-17 Physics Colloquium Message-ID: <200705130741.KAA22460647@tzin.bgu.ac.il> Physics Colloquium DATE: 17-05-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Crackling noise and complexity in natural systems SPEAKER: Gianfranco Durin , Istituto Nazionale di Ricerca Metrologica (I.N.Ri.M), Torino, Italy ABSTRACT/COMMENTS: Is there any relation between a devastating earthquake, a snow avalanche, some drops of water in a sponge, or a ferromagnet along an hysteresis loop? Despite huge differences, all these natural systems respond to external perturbations by a burst of events on a broad range of sizes. This random response is commonly termed as \'crackling noise\', and represents a common feature of many complex systems. After a general introduction of the main features of this noise, we aim to present the most recent results in the particular crackling noise produced in soft magnetic materials, known as Barkhausen noise. Many of the theoretical and experimental results obtained in ferromagnets can in fact be applied with success to the study of other complex systems. This helps us to understand complexity within a more general theoretical framework, and focus the role of criticality and universality to set the noise properties. Refreshments are served at 3:20pm From physics at bgu.ac.il Mon May 14 09:23:32 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-16 Physical Chemistry Seminar Message-ID: <200705140623.JAA23323543@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 16-05-2007 TIME: 16:00 PLACE: Bldg. 26, Room 112 (first floor) TITLE: \"Predicting the properties of novel electronic materials from first principles\" SPEAKER: Dr. Leeor Kronik, Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100 ABSTRACT/COMMENTS: Three exciting developments in the field of semiconductor science are the emergence of nano-materials, of spintronic materials, and of hybrid organic-semiconductor structures. In nano-materials, size is used as a means of modifying systematically the electronic and optical properties of matter. In spintronic materials, addition of magnetic impurities can result in materials that are semiconducting and ferromagnetic at the same time. In organicsemiconductor structures, the power of organic chemistry is harnessed for rational design of semiconductor interface properties. Here, I will present ab initio calculations for all three classes of materials, based on density functional theory, that elucidate the mechanisms controlling size-induced, magnetic-impurity-induced, and organic-adsorption-induced changes in electronic structure. I will then show how these explain novel, experimentally observed electrical, magnetic, and optical properties of such materials. From physics at bgu.ac.il Mon May 14 09:27:09 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-20 Special Seminar Message-ID: <200705140627.JAA23206395@tzin.bgu.ac.il> Special Seminar DATE: 20-05-2007 TIME: 14:00 PLACE: Bldg. 29 Room 306 (Seminar Room) TITLE: \"Molecular control of the electronic and magnetic properties of solid state surfaces and devices\" SPEAKER: Itai Carmeli, Center for Nano-Science, department of Physical Chemistry, Tel-Aviv University ABSTRACT/COMMENTS: Self assembly of organized monolayers of molecules on solid state surfaces is an efficient and powerful tool that has application ranging from the passivation of surfaces to the construction of nano-scale electronic devices. In this talk several novel applications such as the modulation of the electronic and magnetic properties of surfaces and the fabrication of electronic devices will be demonstrated. A unique occurrence in which magnetism appears ex nihilo, when organic molecules are self-assembled as monolayers on gold substrate will be demonstrated. The molecules as well as the substrate, when they stand alone, are diamagnetic. An overview on the current status of the field of “surface magnetism” will be given. Molecular adsorption can be used as a tool to enhance the magnetic properties of the ferromagnetic semiconductor MnGaAs. We observe that adsorption of selected organic molecules produces striking, anisotropic changes in the low-temperature magnetization. These changes accompany the emergence of a small ferromagnetic component with Curie temperature more than four times larger than that of the unmodified heterostructure. In addition a novel method to control the bang gap of photonic crystal by molecular adsorption of a single monolayer will be presented. The photonic crystal is shown to be sensitive to the monolayer quality and to the dielectric constant of the fi lm. The electronic coupling between a photoactive protein photosystem I (PS I) and semiconductors, metals and carbon nanotubes is used for fabrication of hybrid bio-solid-state electrooptical devices. The robust cyanbacterial nano-sized protein-chlorophyll complex PS I can generates photovoltage of 1 V with internal energy conversion efficiency of 58% (~23% for solar energy), quantum efficiency of ~1 in dry environment, is used as a phototransistor gate and for the construction of photovoltaic devices. Functional oriented junctions are fabricated by covalently binding genetically engineered cysteine mutants of PS I proteins to GaAs, metal surfaces and carbon nanotubes. A photovoltage of 0.5 V generated by the dry oriented monolayer of PS I protein on transistor channels, can be use to develop highly sensitive photon counting detectors. Placed between a metal electrode and a transparent conducting glass PS I nano photovoltaic cell generated, in preliminary results, photocurrent of 1.7 mA/cm2 with energy conversion efficiency of 1.4% (Internal 34%). Covalent binding of PS I to carbon nanotubes is used for the study and construction of nano-size optoelectronic photocells and sensors for light. From band at bgu.ac.il Mon May 14 09:27:42 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-23 Physical Chemistry Seminar Message-ID: <200705140627.JAA23178511@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 23-05-2007 TIME: 4:00 PM (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Direct observation of proton solvates in aqueous solutions SPEAKER: Professor Ehud Pines, Ben-Gurion University ABSTRACT/COMMENTS: Understanding proton solvation by water is still largely an open question of great importance which does not cease to generate much interest. Step-wise solvation of the proton by water is observed in the liquid by mixing protonated water with various amounts of non-hydrogen-bonding solvents and when directly observing transient water switches in acid-base reactions [1-3]. By combining vibrational spectroscopy with various photoacid-induced proton-transfer-to- water studies and with measuring the electric conductivity of protonated water/co-solvent solutions we progress toward unveiling the nature and the solvation state of the aqueous proton. 1. O. F. Mohammed, D. Pines, J. Dreyer, E. Pines, E. T. J. Nibbering, Science, 2005, 310, 83. 2. O. F. Mohammed, D. Pines, E. T. J. Nibbering, E. Pines, Angew. Chem. Intl. Ed., 2007, 46, 1458. 3. J. T. Hynes, Nature, 2007, 446, 271. From jung at bgu.ac.il Tue May 15 08:24:35 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-21 Condensed Matter Seminar Message-ID: <200705150524.IAA24037826@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 21-05-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: THE RISE and FALL of DECOHERENCE SPEAKER: Professor Philip C.E. Stamp, Pacific Institute of Theoretical Physics and University of British Columbia ABSTRACT/COMMENTS: Decoherence was at one time viewed as a rather mysterious and problem associated with the foundations of quantum mechanics, and hardly amenable to theoretical or experimental analysis. We now have a detailed understanding of the mechanisms of decoherence in atomic physics and quantum optics, and in some condesned matter systems (although speculation is still rife in cosmology). In condensed matter systems, decoherence comes from interaction with either delocalised modes (oscillator baths) or localised modes (spin baths). These 2 baths behave quite differently, with spin baths causing much more decoherence but much less dissipation than oscillator baths. Many experiments have been done in superconducting, conducting, magnetic, and atomic systems to bear this out. But how may we control decoherence, and reduce it to very low levels? This is essential for quantum information processing, or for any ther large-scale quantum phenomenon. The most challenging problem is to control the decoherence of multi-particle or multi-system entanglement. These problems reach to the heart of what we understand about quantum mechanics. This talk will review both the theoretical and experimental progress and challenges. From gideonc at bgu.ac.il Wed May 16 14:27:21 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-17 Physics Colloquium - Reminder Message-ID: <200705161127.OAA25088809@tzin.bgu.ac.il> Physics Colloquium - Reminder DATE: 17-05-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Crackling noise and complexity in natural systems SPEAKER: Prof. G. Durin, Istituto Nazionale di Ricerca Metrologica (I.N.Ri.M), Torino, Italy ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Durin.html Refreshments are served at 3:20pm From gideonc at bgu.ac.il Thu May 17 18:02:11 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-24 Physics Colloquium Message-ID: <200705171502.SAA25396581@tzin.bgu.ac.il> Physics Colloquium DATE: 24-05-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Surface-Plasmon Enhancement in Random Lasers SPEAKER: Prof. Dan Davidov, Racah Institute of Physics, The Hebrew University of Jerusalem ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Davidov.html Refreshments are served at 3:20pm From band at bgu.ac.il Mon May 21 13:07:30 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-30 Physical Chemistry Seminar Message-ID: <200705211007.NAA28498130@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 30-05-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Sisyphus-like cooling in a bistable cavity SPEAKER: Professor Ilya Averbukh, Weizmann Institute of Science ABSTRACT/COMMENTS: We propose a generic approach to nonresonant laser cooling of atoms/molecules in a bistable optical cavity. The method exemplifies a photonic version of Sisyphus cooling, in which the matter-dressed cavity extracts energy from the particles and discharges it to the external field as a result of sudden transitions between two stable states. From ibar at bgu.ac.il Fri May 25 11:18:04 2007 From: ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-29 Lasers Seminar Message-ID: ANNOUNCEMENT==> DATE: 29-05-2007 TIME: 15:30 pm (Tue) PLACE: Physics club (Building 29, room 002) TITLE: Hydrodynamic Instability in Inertial Confinement Fusion Application SPEAKER: Dr. Oren Sadot Nuclear Research Center Negev, Israel Laboratory for Laser Energetics, University of Rochester USA. ABSTRACT The Rayleigh?Taylor (RT) instability is a subject of intensive experimental and theoretical research because of its critical importance in inertial confinement fusion (ICF) and astrophysics. In ICF application, an imploding outer spherical shell is pushed by an intense radiation field toward the center. The nuclear fuel inside the shell is compressed and heated until reaching ignition conditions. The RT instability that is developed on the fuel?shell surface can lead to target disruption and the degradation of implosion performance. In the first part of the talk, the ICF principle, technique and facilities will be overviewed. In the second part, new results from a recent study on the RT instability late time evolution under intense laser conditions will be presented. The study was carried out using the OMEGA facility at the Rochester University NY USA. Prof. I. Bar Department of Physics Ben-Gurion University of the Negev Beer Sheva 84105 ISRAEL? -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070525/ff8a0f8b/attachment.htm From jung at bgu.ac.il Sun May 27 12:55:42 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-28 Condensed Matter Seminar Message-ID: <200705270955.MAA34071843@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 28-05-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Linear Positive magnetoresistance and Quantum Interference in Ferromagnetic Metals SPEAKER: Alexander Gerber, Tel Aviv University School of Physics and Astronomy ABSTRACT/COMMENTS: From physics at bgu.ac.il Sun May 27 13:16:36 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-30 Physical Chemistry Seminar Message-ID: <200705271016.NAA34141694@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 30-05-2007 TIME: 16:00 PLACE: Bldg. 29, Room 306 (Seminar Room) TITLE: \"Sisyphus-like cooling in a bistable cavity\" SPEAKER: Professor Ilya Averbukh, Weizmann Institute of Science ABSTRACT/COMMENTS: We propose a generic approach to nonresonant laser cooling of atoms/molecules in a bistable optical cavity. The method exemplifies a photonic version of Sisyphus cooling, in which the matter-dressed cavity extracts energy from the particles and discharges it to the external field as a result of sudden transitions between two stable states. From gideonc at bgu.ac.il Sun May 27 16:29:03 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-05-31 Physics Colloquium Message-ID: <200705271329.QAA34160490@tzin.bgu.ac.il> Physics Colloquium DATE: 31-05-2007 TIME: PLACE: TITLE: Due to the (cancelled) Student Day there will be no Colloquium this week. SPEAKER: , ABSTRACT/COMMENTS: From nano at bgu.ac.il Wed May 30 10:14:33 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-06 nanotechnology workshop Message-ID: <003801c7a28a$2c815b10$1b0e4884@estinano> Nanotechnology workshop, Wednesday June 6, 12:00 building 29, room 306,Chemistry Department seminar room Title : Dynamic aspects of protein adsorption on charged bilayers Speaker:Daniel Harries Department of Physical Chemistry The Hebrew University, Jerusalem Abstract: As charged macromoleculules adsorb and diffuse on oppositely charged lipid membranes, they can attract or repel lipids, resulting in lateral membrane rearrangement. We present a dynamic mean-field model that allows to self-consistently find the equilibrium state of membrane-protein complexes upon rearrangement in 3D and at the atomic level, while also informing on the time evolution of lipid lateral re-organization during adsorption. We find that lipid composition plays a crucial role in determining whether diffusing proteins will be able to sequester lipids and to elastically deform membranes. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070530/a6a4193b/attachment.htm From band at bgu.ac.il Wed May 30 10:53:58 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-06 Physical Chemistry Seminar Message-ID: <200705300753.KAA36711376@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 06-06-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Nanoscopic Spin-Frustrated Cluster V15: Antisymmetric Exchange and Instability SPEAKER: Professor Boris Tsukerblat, Ben-Gurion University ABSTRACT/COMMENTS: In the context of the continuous interest in single molecule magnetism, much attention has been focused on the unique layered large vanadium(IV) cluster K_{6}[V^{IV}_{15}As_{6}O_{42}(H_{2}O)]·8H_{2}O (hereafter called V15) containing fifteen V^{IV} ions strongly coupled through antiferromagnetic exchange to give the spin frustrated ground state. Here we give an overview of the magnetic properties of V15 with emphasis on the concept of spin frustration and the special role of antisymmetric (AS) exchange and vibronic instability in spin frustrated systems. The following questions will be discussed: 1) pattern of spin-levels of V15 molecule and a three-spin model. AS exchange: analysis of degeneracy and symmetry conditions, spin frustration and the special role of the AS exchange; 2) magnetic anisotropy, symmetry rules for crossing/anticrossing in the Zeeman pattern; 3) stepwise behavior of the adiabatic magnetization versus field at low temperatures, discussion of the experimental data; 4) selection rules in EPR, high-frequency experimental data; 5) magneto-elastic interactions and structural instability in spin-frustrated systems, competitive influence of the AS exchange and Jahn-Teller interaction on magnetic anisotropy. From jung at bgu.ac.il Wed May 30 14:34:11 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-04 Condensed Matter Seminar Message-ID: <200705301134.OAA36821011@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 04-06-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Manipulating magnetic domain-walls with current in SrRuO3 SPEAKER: Prof. Lior Klein, Department of Physics Bar-Ilan University ABSTRACT/COMMENTS: Developing future spintronic devices (i.e., electronic devices that make use of the spin of the electron) faces the challenge of manipulating the magnetic state of a nanoscale magnetic element without affecting its magnetic neighbors or generating excessive heating. A promising route for achieving this goal is by using spin-polarized current for displacing a domain wall separating two magnetic domains. Therefore, it has become of particular interest to elucidate the mechanisms responsible for current-induced domain wall displacement (CIDWD) and determine the factors that affect its efficiency. In our study, we have explored CIDWD in the ferromagnetic perovskite SrRuO3 which is characterized by extremely narrow domain-wall width (~3 nm) attributed to its large uniaxial magnetocrystalline anisotropy (anisotropy field of ~10 T). Using sub-micrometer fabricated patterns of high-quality epitaxial films SrRuO3, we monitored (by measuring the extraordinary Hall effect) the introdu ction and current-induced manipulation of a single domain wall and thus we were able to determine the current required for displacing the domain wall in a wide range of temperatures. We found that current density in the range of 10^9 - 10^10 A/m2 is sufficient for domain-wall displacement. These results indicate orders of magnitude higher efficiency of the current in displacing domain walls which we believe is related to the narrow width of domain walls in this compound. These results are an important step toward creating a new generation of high-density spintronic devices based on nanoscale magnetic elements. From gideonc at bgu.ac.il Thu May 31 20:02:53 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-07 Physics Colloquium Message-ID: <200705311702.UAA38026266@tzin.bgu.ac.il> Physics Colloquium DATE: 07-06-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Towards DNA- and Protein-Based Nanoelectronics? SPEAKER: Dr. Danny Porat, Dept. of Chemistry, Hebrew University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Porat.html Refreshments are served at 3:20pm From physics at bgu.ac.il Sun Jun 3 10:19:37 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-10 Seminar in Inorganic Chemistry Message-ID: <200706030719.KAA40628796@tzin.bgu.ac.il> Seminar in Inorganic Chemistry DATE: 10-06-2007 TIME: 20:00 PLACE: Bldg. 29 Room 306 TITLE: \"Reduction of Alkenes in Aqueous Solutions\" SPEAKER: Schutz Osnat , (Doctoral Lecture) ABSTRACT/COMMENTS: Alkenes are known to form dŠp* complexes with low valent transition metal ions. Recently it was shown that a Ni(I) complex with a tetraazamacrocyclic ligand (cyclam), reduces maleic acid. It was decided to investigate whether this is a general reaction of low valent transition metal complexes. In the present study the reactions of CoIL, NiIL (L=5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) and NiIL1 (L1=5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane) with maleic acid were investigated. Therefore, the effect of addition of maleate to aqueous solutions containing these low valent metal complexes, prepared via the pulse radiolytic technique was studied. The dŠp* complexes formed between the monovalent cobalt and nickel complexes and maleate were detected and characterized by UV-Vis spectroscopy. The nature of the final products formed was studied and detailed mechanisms of the reduction processes are proposed. The results point out that all the monovalent complexes investigated reduce maleate. The CoIL complex reduces less maleate than the other complexes as several side reactions occur. NiIL reduces maleate to succinate even better than the cyclam complex as this complex also produces a dimer of the maleate and higher molecular weight products. From Ibar at bgu.ac.il Mon Jun 4 08:24:43 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-05 Lasers Seminar Message-ID: <00a201c7a668$a89a42c0$d10f4884@ilap> ANNOUNCEMENT==> DATE: 05-06-2007 TIME: 15:30 pm PLACE: Physics club (Building 29, room 002) TITLE: Molecular Dynamics of vibrationally excited methylamine SPEAKER: Mr. Uzi Zecharia Department of Physics, Ben Gurion University of the Negev ABSTRACT Vibrationally mediated photodissociation involves laser techniques that deposit energy in skeletal motions of molecules, which subsequently interact with photons promoting them to excited electronic states. The molecules dissociate, releasing atomic photofragments. Action and Doppler spectroscopies, expressing the yield of the ensuing fragments vs. the vibrational excitation and UV probe laser wavelengths, respectively, are measured. These spectra together with the simultaneously measured photoacoustic spectra provide a unique means for accessing the dynamics on the ground and excited potential energy surfaces. Application of these spectroscopies to the model molecule, methylamine, illustrates their potential in getting detailed information on energy flow within vibrationally excited molecules, in determining pathways for energy redistribution and in obtaining insight on the photodissociation process. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070604/045b5ec0/attachment.htm From gideonc at bgu.ac.il Mon Jun 4 15:34:33 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-07 Physics Colloquium reminder Message-ID: <200706041234.PAA41517415@tzin.bgu.ac.il> Physics Colloquium reminder DATE: 07-06-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Towards DNA- and Protein-Based Nanoelectronics? SPEAKER: Dr. Danny Porat, Dept. of Chemistry, Hebrew University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Porat.html Refreshments are served at 3:20pm From Ibar at bgu.ac.il Tue Jun 5 17:26:34 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-12 Lasers Seminar Message-ID: <01a901c7a77d$8535bab0$d10f4884@ilap> ANNOUNCEMENT==> DATE: 12-06-2007 TIME: 15:30 pm PLACE: Physics club (Building 29, room 002) TITLE: Opto-acoustic solitons in Bragg gratings SPEAKER: Dr. Richard S. Tasgal Department of Chemistry, Ben Gurion University of the Negev ABSTRACT: Optical gap solitons, which exist due to a balance of nonlinearity and dispersion due to a Bragg grating, can couple to acoustic waves through electrostriction. This gives rise to a new species of "gap-acoustic" soliton (GAS), for which we find exact analytic solutions. The GAS consists of an optical pulse similar to the optical gap soliton, dressed by an accompanying phonon pulse. In subsonic (supersonic) solitons, the phonon pulse is a positive (negative) density variation. Close to the speed of sound, the phonon component is large. Coupling to the acoustic field damps the solitons' oscillatory instability, and gives rise to a distinct instability for supersonic solitons, which may either make the GAS sharply change speed and direction, or destroy the soliton. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070605/8eb1c8d8/attachment.htm From nano at bgu.ac.il Wed Jun 6 12:22:09 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-13 nanotechnology workshop Message-ID: <006e01c7a81c$28c68d00$1b0e4884@estinano> Nanotechnology workshop, Wednesday June 13, 12:00 building 29, room 306,Chemistry Department seminar room Title : Dynamics of septum formation in E. coliSpeaker:Mario Feingold Department of Physics Ben Gurion University -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20070606/dc89d5f5/attachment.htm From band at bgu.ac.il Wed Jun 6 12:59:45 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-13 Physical Chemistry Seminar Message-ID: <200706060959.MAA43381271@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 13-06-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: SPEAKER: Professor Ehud Pines, Ben-Gurion University ABSTRACT/COMMENTS: Understanding proton solvation by water is still largely an open question of great importance which does not cease to generate much interest. Step-wise solvation of the proton by water is observed in the liquid by mixing protonated water with various amounts of non-hydrogen-bonding solvents and when directly observing transient water switches in acid-base reactions [1-3]. By combining vibrational spectroscopy with various photoacid-induced proton-transfer-to- water studies and with measuring the electric conductivity of protonated water/co-solvent solutions we progress toward unveiling the nature and the solvation state of the aqueous proton. 1. O. F. Mohammed, D. Pines, J. Dreyer, E. Pines, E. T. J. Nibbering, Science, 2005, 310, 83. 2. O. F. Mohammed, D. Pines, E. T. J. Nibbering, E. Pines, Angew. Chem. Intl. Ed., 2007, 46, 1458. 3. J. T. Hynes, Nature, 2007, 446, 271. From band at bgu.ac.il Wed Jun 6 14:04:30 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-13 Physical Chemistry Seminar Message-ID: <200706061104.OAA43435767@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 13-06-2007 TIME: 4:00 PM (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: Direct observation of proton solvates in aqueous solutions SPEAKER: Professor Ehud Pines, Ben-Gurion University ABSTRACT/COMMENTS: Understanding proton solvation by water is still largely an open question of great importance which does not cease to generate much interest. Step-wise solvation of the proton by water is observed in the liquid by mixing protonated water with various amounts of non-hydrogen-bonding solvents and when directly observing transient water switches in acid-base reactions [1-3]. By combining vibrational spectroscopy with various photoacid-induced proton-transfer-to- water studies and with measuring the electric conductivity of protonated water/co-solvent solutions we progress toward unveiling the nature and the solvation state of the aqueous proton. 1. O. F. Mohammed, D. Pines, J. Dreyer, E. Pines, E. T. J. Nibbering, Science, 2005, 310, 83. 2. O. F. Mohammed, D. Pines, E. T. J. Nibbering, E. Pines, Angew. Chem. Intl. Ed., 2007, 46, 1458. 3. J. T. Hynes, Nature, 2007, 446, 271. From gideonc at bgu.ac.il Sun Jun 10 11:00:59 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-14 Physics Colloquium Message-ID: <200706100800.LAA46298271@tzin.bgu.ac.il> Physics Colloquium DATE: 14-06-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Due to the Student Day there will be no Colloquium this week. SPEAKER: , ABSTRACT/COMMENTS: Refreshments are served at 3:20pm From jung at bgu.ac.il Sun Jun 10 11:08:17 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-11 Condensed Matter Seminar Message-ID: <200706100808.LAA47135478@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 11-06-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: No seminar this week. You are invited to participate in the conference \"Fluctuations and Phase Transitions in Superconductors\". For details see http://braude.ort.org.il/conf/Superconductors/ SPEAKER: , ABSTRACT/COMMENTS: From physics at bgu.ac.il Sun Jun 10 14:51:10 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-13 Physical Chemistry Seminar Message-ID: <200706101151.OAA47210740@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 13-06-2007 TIME: 16:00 PLACE: Bldg. 29, Room 306 (Seminar Room) TITLE: \"Direct observation of proton solvates in aqueous solutions\" SPEAKER: Professor Ehud Pines, Department of Chemistry Ben-Gurion University of the Negev, Beer-Sheva ABSTRACT/COMMENTS: Understanding proton solvation by water is still largely an open question of great importance which does not cease to generate much interest. Step-wise solvation of the proton by water is observed in the liquid by mixing protonated water with various amounts of non-hydrogen-bonding solvents and when directly observing transient water switches in acid-base reactions [1-3]. By combining vibrational spectroscopy with various photoacid-induced proton-transfer-to- water studies and with measuring the electric conductivity of protonated water/co-solvent solutions we progress toward unveiling the nature and the solvation state of the aqueous proton. From physics at bgu.ac.il Sun Jun 10 14:55:24 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-10 Seminar in Inorganic Chemistry Message-ID: <200706101155.OAA47256352@tzin.bgu.ac.il> Seminar in Inorganic Chemistry DATE: 10-06-2007 TIME: 20:00 PLACE: Bldg.29  Room 306 (Seminar Room) TITLE: \"Reduction of Alkenes in Aqueous Solutions\" SPEAKER: Schutz Osnat, (Doctoral Lecture) ABSTRACT/COMMENTS: Alkenes are known to form d* complexes with low valent transition metal ions. Recently it was shown that a Ni(I) complex with a tetraazamacrocyclic ligand (cyclam), reduces maleic acid. It was decided to investigate whether this is a general reaction of low valent transition metal complexes. In the present study the reactions of CoIL, NiIL (L=5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) and NiIL1 (L1=5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane) with maleic acid were investigated. Therefore, the effect of addition of maleate to aqueous solutions containing these low valent metal complexes, prepared via the pulse radiolytic technique was studied. The d* complexes formed between the monovalent cobalt and nickel complexes and maleate were detected and characterized by UV-Vis spectroscopy. The nature of the final products formed was studied and detailed mechanisms of the reduction processes are proposed. The results point out that all the monovalent complexes investigated reduce maleate. The CoIL complex reduces less maleate than the other complexes as several side reactions occur. NiIL reduces maleate to succinate even better than the cyclam complex as this complex also produces a dimer of the maleate and higher molecular weight products. From jung at bgu.ac.il Sun Jun 17 12:12:05 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-18 Condensed Matter Seminar Message-ID: <200706170912.MAA2376801@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 18-06-2007 TIME: 11:30am (Mon) PLACE: Physics club (Building 29, room 002) TITLE: Transport and other properties of disordered superconductinhg thin films SPEAKER: Yonatan Dubi, Physics Department Ben Gurion University ABSTRACT/COMMENTS: Experimental studies of magnetoresistance in disordered superconducting (SC) thin films reveal an abundance of unexpected results, such as a huge peak in the magnetoresistance on the insulating side of the super-conductor-insulator transition which evolves as the field is tilted, and traces of superconducting correlations that survive well above the transition. We present a phenomenological theory that accounts for these finding (especially the non-monotonic magnetoresistance) in terms of the formation of SC islands, which leads to a competition between Coulomb-blockaded Cooper-pairs and normal electrons. The theory is accompanied by extensive numerical calculations to support it, in which a locally self-consistent solution of the BdG equations in the presence of disorder and tilted magnetic field is obtained. Simple arguments from percolation theory are then used to explain more experimental findings, such as the non-monotonic magnetoresistance in parallel field and the relation between the critical field and the magnetic field tilt angle. Finally, Monte-Carlo simulations are used to demonstrate the relation between the real-space structure and the SC-insulator transition. From physics at bgu.ac.il Sun Jun 17 12:51:11 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-21 Physics Colloquium Message-ID: <200706170951.MAA2418947@tzin.bgu.ac.il> Physics Colloquium DATE: 21-06-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: The Origin of Two Galaxy Types SPEAKER: Avishai Dekel , Racah Institute of Physics, The Hebrew University of Jerusalem ABSTRACT/COMMENTS: The emergence of a concordance cosmological model based on cold dark matter and dark energy has triggered a new phase in the study of galaxy formation, in which the framework is known. A flood of multi-wavelength data from space and ground telescopes is revolutionizing our knowledge of axies, both today and in the distant past, introducing interesting theoretical challenges. This talk will address the fundamental question of physical cosmology: the origin of the two major types of galaxies. One population is the ``blue cloud\" of star-forming disk galaxies in the field and the other is the ``red sequence\" of dead ellipticals in clusters. We will explain the origin of the characteristic mass separating these populations, and address the main physical processes responsible for the properties of the two galaxy types. Refreshments are served at 3:20pm From jung at bgu.ac.il Mon Jun 18 14:39:02 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-21 Condensed Matter Seminar Message-ID: <200706181139.OAA3444352@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 21-06-2007 TIME: 11:30am (Thu) NOTE SPECIAL DATE PLACE: Physics club (Building 29, room 002) TITLE: Coherent Lattice Vibrations in Superconductors SPEAKER: Prof. Alan M. Kadin, Hypres, Inc., Elmsford, New York, USA ABSTRACT/COMMENTS: Conventional superconductivity is believed to derive from interaction between electrons and phonons, but a consistent physical picture of this interaction has been lacking. A new picture of diffracting electron and phonons waves is presented, with macroscopic wave patterns that are coherent across the entire superconductor. A similar picture that involves coherent spin waves may apply for the high temperature superconducting cuprates. The coherent wave patterns should be directly measurable using x-ray and neutron diffraction in the superconducting state. *See ArXiv preprint http://www.arxiv.org/abs/0706.0338 From jung at bgu.ac.il Thu Jun 21 08:19:58 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-21 Condensed Matter Seminar Message-ID: <200706210519.IAA5903527@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 21-06-2007 TIME: 11:30am (Thursday) - Special Seminar - TODAY PLACE: Physics club (Building 29, room 002) TITLE: Coherent Lattice Vibrations in Superconductors SPEAKER: Prof. Alan M. Kadin, Hypres, Inc., Elmsford, New York, USA ABSTRACT/COMMENTS: Conventional superconductivity is believed to derive from interaction between electrons and phonons, but a consistent physical picture of this interaction has been lacking. A new picture of diffracting electron and phonons waves is presented, with macroscopic wave patterns that are coherent across the entire superconductor. A similar picture that involves coherent spin waves may apply for the high temperature superconducting cuprates. The coherent wave patterns should be directly measurable using x-ray and neutron diffraction in the superconducting state. *See ArXiv preprint http://www.arxiv.org/abs/0706.0338 Prof. Kadin is Senior Scientist at Hypres, Inc., a small company near New York City that is developing ultrafast superconducting electronic circuits and systems (http://www.hypres.com). (The present talk is not directly related to Hypres business.) Prof. Kadin has 30 years of experience in superconducting devices and materials. Prior to coming to Hypres in 2000, Prof. Kadin was a faculty member at the University of Rochester in New York. From gideonc at bgu.ac.il Mon Jun 25 10:25:48 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-28 Physics Colloquium Message-ID: <200706250725.KAA9180377@tzin.bgu.ac.il> Physics Colloquium DATE: 28-06-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Electric Fields: From Copolymer Orientation to Phase-Transitions and Chemical Reactions in Liquid Mixtures SPEAKER: Dr. Yoav Tsori, Dept. of Chemical Engineering, Ben Gurion University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Tsori.html Refreshments are served at 3:20pm From jung at bgu.ac.il Tue Jun 26 17:23:29 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-07-02 Condensed Matter Seminar Message-ID: <200706261423.RAA10301684@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 02-07-2007 TIME: 11:30am (Mon) PLACE: New Physics club (NEW Building) TITLE: THE RISE and FALL of DECOHERENCE SPEAKER: Professor Philip CE Stamp, Pacific Institute of Theoretical Physics and University of British Columbia ABSTRACT/COMMENTS: Decoherence was at one time viewed as a rather mysterious and problem associated with the foundations of quantum mechanics, and hardly amenable to theoretical or experimental analysis. We now have a detailed understanding of the mechanisms of decoherence in atomic physics and quantum optics, and in some condesned matter systems (although speculation is still rife in cosmology). In condensed matter systems, decoherence comes from interaction with either delocalised modes (oscillator baths) or localised modes (spin baths). These 2 baths behave quite differently, with spin baths causing much more decoherence but much less dissipation than oscillator baths. Many experiments have been done in superconducting, conducting, magnetic, and atomic systems to bear this out. But how may we control decoherence, and reduce it to very low levels? This is essential for quantum information processing, or for any other large-scale quantum phenomenon. The most challenging problem is to control the decoherence of multi-particle or multi-system entanglement. These problems reach to the heart of what we understand about quantum mechanics. This talk will review both the theoretical and experimental progress and challenges. From jung at bgu.ac.il Wed Jun 27 09:22:10 2007 From: jung at bgu.ac.il (jung@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-07-02 Condensed Matter Seminar Message-ID: <200706270622.JAA10793209@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 02-07-2007 TIME: 11:30am (Mon) PLACE: NEW Physics club (NEW Building) TITLE: Renormalization Group Method for Quasi 1D Systems (PLEASE IGNORE PREVIOUS ERRATIC E-MAIL ANNOUNCEMENT) SPEAKER: Samuel Moukouri, University of Michigan ABSTRACT/COMMENTS: The low-temperature electronic properties of a large class of solids, including quasi 1D and 2D organic conductors, quasi 1D inorganic superconductors, cuprate superconductors and quasi 1D quantum antiferromagnets, are dominated by the combined effects of low dimensionality and competing interactions. As a consequence of these effects, these properties depart from the conventional Fermi liquid and BCS theories. It has recently been suggested that ground-state transitions between these new intriguing phases may themselves fall outside the Landau-Ginzburg-Wilson theory. Using a recently proposed renormalization group scheme, I explore the emergence of this new physics in models for quasi 1D systems. I will first study a quantum phase transition in a simple model of frustrated magnets. I will show evidence of an extension of the Haldane conjecture to anisotropic 2D systems and of a breakdown of the Landau-Ginzburg-Wilson theory. Then I will present a study of the competition between antiferromagnetism and superconductivity in a model of quasi 1D organic conductors. I will discuss the nature of antiferromagnetism in this model and show that it captures the essential of the physics of these materials. From gideonc at bgu.ac.il Wed Jun 27 14:53:52 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-06-28 Physics Colloquium - Reminder Message-ID: <200706271153.OAA10965307@tzin.bgu.ac.il> Physics Colloquium - Reminder DATE: 28-06-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Electric Fields: From Copolymer Orientation to Phase-Transitions and Chemical Reactions in Liquid Mixtures SPEAKER: Dr. Yoav Tsori, Dept. of Chemical Engineering, Ben Gurion University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Tsori.html Refreshments are served at 3:20pm From gideonc at bgu.ac.il Sun Jul 1 15:52:14 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-07-05 Physics Colloquium Message-ID: <200707011252.PAA14183970@tzin.bgu.ac.il> Physics Colloquium DATE: 05-07-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: On the ability of cells to evolve into novel life forms SPEAKER: Prof. Erez Braun , Department of Physics, Technion ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collp06_files/Braun.html Refreshments are served at 3:20pm From hbaruch at bgu.ac.il Thu Jul 5 17:37:19 2007 From: hbaruch at bgu.ac.il (hbaruch@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-07-09 Condensed Matter Seminar Message-ID: <200707051437.RAA17518588@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 09-07-2007 TIME: 11:30am (Mon) PLACE: Physics club (new building) TITLE: Interference, renormalization and dephasing of a particle in dissipative environments SPEAKER: Prof. Baruch Horovitz, Department of Physics, Ben-Gurion University ABSTRACT/COMMENTS: From physics at bgu.ac.il Wed Sep 5 08:57:17 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-09-06 Special Seminar Message-ID: <200709050557.IAA39371135@tzin.bgu.ac.il> Special Seminar DATE: 06-09-2007 TIME: 13:00 PLACE: Physics Build (#54), Seminar Room # 207 TITLE: \"Properties of Nuclear Matter From Excitations of Nuclei\" SPEAKER: Professor Shalom Shlomo, Cyclotron Institute, Texas A&M University, College Station, USA ABSTRACT/COMMENTS: Nuclear matter (NM) bulk properties, such as binding energy per nucleon, neutron and proton densities, incompressibility coefficient K and symmetry energy coefficient J, are important physical quantities needed for determining the equation of state (EOS) of NM. The EOS is an important ingredient in the study of properties of nuclei, supernova collapse, neutron star and heavy-ion collisions. We will discuss the predictive power of Hartree-Fock (HF) mean-field approximation for the nuclear many-body system in determining properties of finite nuclei and thereby in extracting bulk properties of infinite NM by extrapolation. In particular, we will review the current status of determining the value of K, considering the most sensitive method of analyzing the recent accurate experimental data on excitation strengths of compression modes of nuclei within microscopic relativistic and non-relativistic theoretical models. We will discuss the consequences of common violations of self-consistency in HF based random phase-approximation calculations of strength functions and present results of highly accurate calculations of centroid energies and excitation cross sections of giant resonances. Explanations (resolutions) of long standing discrepancies in the value of K will be presented. From physics at bgu.ac.il Tue Oct 9 12:41:45 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-10-16 Chemical Physics Seminar Message-ID: <200710091041.MAA72508652@tzin.bgu.ac.il> Chemical Physics Seminar DATE: 16-10-2007 TIME: 15:30 PLACE: Bldg. 29 Room 306 (Seminar Room) TITLE: \"Electron quantization and wave propagation in nanotube lattices and molecular encapsulation in nanotubes\" SPEAKER: Dr. Hossein Sadeghpour, Institute for Theoretical Atomic, Molecular, and Optical Physics (ITAMP) Harvard-Smithsonian Center for Astrophysics ABSTRACT/COMMENTS: From physics at bgu.ac.il Sun Oct 14 15:46:24 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-10-25 Physics Colloquium Message-ID: <200710141346.PAA78435421@tzin.bgu.ac.il> Physics Colloquium DATE: 25-10-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Electronic braiding and the Non-Abelian quantum Hall effect SPEAKER: Ady Stern, Condensed Matter Physics, Weizmann Institute of Science ABSTRACT/COMMENTS: I will describe the non-abelian quantum Hall effect and its possible uses for topological quantum computation. I will then focus on several proposed experiments that can serve as litmus tests for identifying non-abelian quantum Hall behavior. Refreshments are served at 3:20pm From physics at bgu.ac.il Mon Oct 15 08:54:43 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-10-22 Particles and Fields Seminar Message-ID: <200710150654.IAA79229460@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 22-10-2007 TIME: 10:00pm (Mon) PLACE: Physics club (Building 54, room207) TITLE: Living without Birkhoff SPEAKER: Dr Irit Maor, ABSTRACT/COMMENTS: Generally,theories of modified gravity violate Birkhoff\'s theore(BT). The severe conceptual and calculational difficulties that arise in the absence of BT are greatly under-appreciated in the literature. The Dvali-Gabadaze-Porrati model (DGP) provides a simple framework where these effects can be explored and quantified. I will explicitly show that the gravitational force exerted by a spherical mass configuration depends on the distribution of the mass,and in particular, is likely non-zero within the shell. A possible conclusion of this work may be that we need BT to hold for a theory to be calculationally tractable. Nature may, of course, refuse to cooperate. From nano at bgu.ac.il Mon Oct 15 10:45:54 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-10-17 nanotechnology workshop Message-ID: <00a801c80f07$cc75f790$1b0e4884@estinano> Skipped content of type multipart/alternative-------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/gif Size: 105 bytes Desc: not available Url : http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071015/fc2def6b/attachment.gif From nano at bgu.ac.il Wed Oct 17 10:37:39 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-10-17 nanotechnology workshop- reminder Message-ID: <007201c81098$fa8d0b40$1b0e4884@estinano> Skipped content of type multipart/alternative-------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/gif Size: 105 bytes Desc: not available Url : http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071017/123934f4/attachment.gif From physics at bgu.ac.il Sun Oct 21 11:51:07 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:26 2009 Subject: [Phys-seminars] 2007-10-24 Astrophysics and Cosmology Seminar Message-ID: <200710210951.LAA86373517@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 24-10-2007 TIME: 12:00 noon (Wed) PLACE: Physics building room 207 TITLE: \"Pulsar Emission Mechanisms\" SPEAKER: Yuri Lyubarsky, Physics Department BGU ABSTRACT/COMMENTS: From aaharony at bgu.ac.il Sun Oct 21 12:24:28 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-10-29 Condensed Matter Seminar Message-ID: <200710211024.MAA87284535@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 29-10-2007 TIME: 11:30am (Mon) PLACE: Physics building room 207 TITLE: Theory of one-dimensional Bose-liquids SPEAKER: Dr. Maxim Khodas, University of Minnesota, School of Physics and Astronomy, Tate Lab of Physics. ABSTRACT/COMMENTS: We analyze the dynamical structure factor of interacting 1D Bose liquids. This quantity has become experimentally accessible in the recent experiments on cold atoms. We find power law non-analyticity in the dynamical structure factor at the kinematical absorption thresholds and power law divergence at the Bogolubov excitation mode. Analytic results are compared with the numerical data. The special limit of strongly interacting bosons is studied using the Bose-Fermi mapping. The numerical data is in agreement with our analytic results. We further discuss the dynamical structure factor at the kinematical thresholds in the weak interaction limit. We argue that it can be understood by considering soliton-like solutions of the semiclassical equations of motion. From nano at bgu.ac.il Wed Oct 24 09:22:24 2007 From: nano at bgu.ac.il (nano@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-10-31 Message-ID: <200710240722.JAA90875458@tzin.bgu.ac.il> DATE: 31-10-2007 TIME: 12:00 PLACE: building 29, room 306,Chemistry Department seminar room TITLE: Observation of Electron-Hole Puddles in Graphene Using a Scanning Single Electron Transistor SPEAKER: Amir Yacoby, Department of Physics, Harvard University, Cambridge ABSTRACT/COMMENTS: The electronic density of states of graphene is equivalent to that of relativistic electrons. In the absence of disorder or doping the Fermi energy lies at the Dirac point where the density of states vanishes. Theory anticipates however that at average zero density the inescapable presence of disorder will lead to electron and hole puddles with equal probability. These puddles may account for the anomalous minimal conductivity observed at zero average density. In this work, we use a scanning single electron transistor to image the carrier density landscape in the vicinity of the neutrality point. Our results confirm the existence of electron-hole puddles. Measurements above the bare Si substrate reveal weak electrostatic disorder that cannot account for the observed density landscape. In the presence of a quantizing magnetic field we image the localization of individual electrons and holes. These provide a quantitative measure of the disorder in graphene. From physics at bgu.ac.il Wed Oct 24 10:54:44 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-10-28 Seminar in Inorganic Chemistry Message-ID: <200710240854.KAA90845142@tzin.bgu.ac.il> Seminar in Inorganic Chemistry DATE: 28-10-2007 TIME: 20:00 PLACE: Bldg. 29 Room 306 TITLE: \"Design and Synthesis of Ligands for High Valent Transition Metal Cations\" SPEAKER: Yael Albo, Ben-Gurion University of the Negev, Department of Chemistry (Doctoral Lecture) ABSTRACT/COMMENTS: Selectivity of metal complexation by ligands is a chemical feature, which has many important technological applications. Examples include metal ore processing, analytical and environmental applications and pharmaceuticals. This study focused on the design and synthesis of ligands for high valent transition metal cations, and characterization of the complexes formed with uranyl, nickel and copper metal cations. For the uranyl ion, the dioxo cation of uranium, ligand design relies upon the equatorial coordination plane (perpendicular to the trans oxo groups) as means of interacting with the metal center. As the two axial positions of the dioxo cation are occupied it was decided to design flexible ligands, which will be able to adjust themselves to the coordination demands of the central metal ion in the equatorial plane. The ability of the ligands to coordinate the uranyl cation was examined with the aim of finding new reagents for the extraction and analytical determination of the cation. For the nickel and copper ions the influence of the ligand structure on the stability of the high valences was examined. Open polydentate and macrocyclic ligands were synthesized, and the redox properties of the complexes were investigated using electrochemistry and pulse radiolysis. From nano at bgu.ac.il Wed Oct 24 12:00:28 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-10-31 nanotechnology workshop Message-ID: <004a01c81624$b5b80970$1b0e4884@estinano> Nanotechnology workshop, Wednesday October 31, 12:00 building 29, room 306,Chemistry Department seminar room Title : Observation of Electron-Hole Puddles in Graphene Using a Scanning Single Electron Transistor Speaker: Amir Yacoby Department of Physics, Harvard University, Cambridge Abstract: The electronic density of states of graphene is equivalent to that of relativistic electrons. In the absence of disorder or doping the Fermi energy lies at the Dirac point where the density of states vanishes. Theory anticipates however that at average zero density the inescapable presence of disorder will lead to electron and hole puddles with equal probability. These puddles may account for the anomalous minimal conductivity observed at zero average density. In this work, we use a scanning single electron transistor to image the carrier density landscape in the vicinity of the neutrality point. Our results confirm the existence of electron-hole puddles. Measurements above the bare Si substrate reveal weak electrostatic disorder that cannot account for the observed density landscape. In the presence of a quantizing magnetic field we image the localization of individual electrons and holes. These provide a quantitative measure of the disorder in graphene. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071024/2cfce1d6/attachment.htm From aaharony at bgu.ac.il Thu Oct 25 12:39:17 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-05 Condensed Matter Seminar Message-ID: <200710251039.MAA92369089@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 05-11-2007 TIME: 11:30am (Mon) PLACE: Physics building room 207 TITLE: Odd-frequency pairing in superconducting heterostructures SPEAKER: Alexander Golubov, Faculty of Science and Technology, University of Twente, The Netherlands ABSTRACT/COMMENTS: We present the theory of odd-frequency pairing in superconducting heterostructures, where quite generally, the odd-frequency pairing component is induced near interfaces. General description of superconducting proximity effect in a normal metal or a ferromagnet attached to an unconventional superconductor (S) is given within quasiclassical kinetic theory for various types of symmetry state in S. As an example, we consider a junction between a diffusive normal metal (DN) and a p-wave superconductor (even-frequency spin-triplet odd-parity symmetry), where the pairing amplitude in a DN belongs to an odd-frequency spin-triplet even-parity symmetry class. Further application of the model is the Josephson effect in SFS junctions where F is fully polarized ferromagnet. Relevance to recent experiments on unconventional junctions is discussed. From gideonc at bgu.ac.il Thu Oct 25 17:35:36 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-01 Physics Colloquium Message-ID: <200710251535.RAA91079424@tzin.bgu.ac.il> Physics Colloquium DATE: 01-11-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Precision measurements with alkali-metal atoms SPEAKER: Prof. Michael Romalis , Department of Physics, Princeton University ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collq0708_A/Romalis.html Refreshments are served at 3:20pm From physics at bgu.ac.il Sun Oct 28 12:26:13 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-08 Physics Colloquium Message-ID: <200710281026.MAA96374361@tzin.bgu.ac.il> Physics Colloquium DATE: 08-11-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Random fields in dilute dipolar magnets. SPEAKER: Moshe Schechter , Dept. of Physics, University of British Colombia, Canada. ABSTRACT/COMMENTS: The ferromagnetic random field Ising model (RFIM) is a central model in the study of random systems. Although used to describe numerous physical systems, its realization in a ferromagnetic system was lacking due to the difficulty in producing random magnetic fields. In this talk I will discuss the recently discovered equivalence of anisotropic dilute dipolar magnets to the Ising model with independently tunable effective random and transverse fields. I will then discuss the implications of this first realization of the RFIM in a ferromagnetic system to the understanding of questions such as classical and quantum phase transitions in random systems, domain wall pinning, and self organized criticality. From physics at bgu.ac.il Sun Oct 28 12:27:00 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-10-29 Particles and Fields Seminar Message-ID: <200710281027.MAA95466038@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 29-10-2007 TIME: 10:00pm (Mon) PLACE: Physics building 54 room 207 TITLE: Topological defects and relevance to cosmology SPEAKER: Ben-Dayan Ido, ABSTRACT/COMMENTS: I\'ll give a pedagogical talk on the issue of topological defects and there relevance to cosmology. The talk will include a simple demonstration of the concept, enumeration of some of the defects (domain walls, monopoles, strings and textures),the topological reasoning, and as much as time permits their relevance to cosmology. From physics at bgu.ac.il Sun Oct 28 12:27:36 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-01 Physics Colloquium Message-ID: <200710281027.MAA95373863@tzin.bgu.ac.il> Physics Colloquium DATE: 01-11-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Precision measurements with alkali-metal atoms SPEAKER: Michael Romalis , Department of Physics, Princeton University ABSTRACT/COMMENTS: Alkali-metal atoms with well-controlled degrees of freedom provide an ideal system for high sensitivity measurements, used, for example, in atomic clocks. I will discuss recent advances in precision measurements using spin-polarized alkali-metal atoms, focusing on their use for detection of weak magnetic fields and searches for physics beyond the Standard Model. The sensitivity of these measurements depends crucially on the electron spin coherence time which is usually limited by atomic collisions. Careful analysis of the collision properties allows one to choose operating regimes where the spin coherence time is increased by several orders of magnitude. With these improvements atomic magnetometers are now surpassing cryogenic SQUID magnetometers which have long been considered most sensitive magnetic field sensors. Higher sensitivity and absence of cryogens open new applications for atomic magnetometers, including detection of nuclear magnetic resonance signals and magnetic fields generated by the brain. For fundamental physics tests, we developed a noble gas-alkali-metal co magnetometer with two spin species occupying the same volume, which allows one to cancel ordinary magnetic fields while retaining sensitivity to exotic effects beyond the Standard Model. Such arrangement is being used to search for Lorentz-violating spin couplings, spin-dependent forces and a CP-violating permanent electric dipole moment. From physics at bgu.ac.il Mon Oct 29 10:15:17 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-10-31 Physical Chemistry Seminar Message-ID: <200710290815.KAA96458272@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 31-10-2007 TIME: 4:00pm (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: \"Theory for an Order-Driven Disruption of the Liquid State in Water\" SPEAKER: Jeremy England, Department of physics, Stanford University ABSTRACT/COMMENTS: From physics at bgu.ac.il Mon Oct 29 15:01:03 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-06 Lasers Seminar Message-ID: <200710291301.PAA97457643@tzin.bgu.ac.il> Lasers Seminar DATE: 06-11-2007 TIME: 3:30pm (Tue) PLACE: Physics building room 207 TITLE: Control of ultracold molecules with an ultrafast frequency comb SPEAKER: Dr Pe\'er, Avi, JILA, University of Colorado USA ABSTRACT/COMMENTS: The ultrafast frequency comb emerged in recent years as a main tool for precision spectroscopy and control. I will describe our recent experiments that utilize the comb for production of deeply bound ultracold polar molecules; these experiments are motivated by the prospects for novel collective quantum phenomena with polar molecules due to their long range dipole-dipole interactions. In the experiment, loosely bound ultracold KRb molecules, produced by Feshbach \'magneto-association\', are driven into more deeply bound states via Raman transitions. While in these experiments, the comb serves as a stable frequency reference, it is possible also to use the comb directly to drive the molecular dynamics with high efficiency and precision. I will review some of our theoretical work in that context as well. From physics at bgu.ac.il Mon Oct 29 15:11:49 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-06 Lasers Seminar Message-ID: <200710291311.PAA97698013@tzin.bgu.ac.il> Lasers Seminar DATE: 06-11-2007 TIME: 3:30pm (Tue) PLACE: Physics building room 207 TITLE: Control of ultracold molecules with an ultrafast frequency comb SPEAKER: Dr Pe\'er, Avi, JILA, University of Colorado,USA ABSTRACT/COMMENTS: The ultrafast frequency comb emerged in recent years as a main tool for precision spectroscopy and control. I will describe our recent experiments that utilize the comb for production of deeply bound ultracold polar molecules; these experiments are motivated by the prospects for novel collective quantum phenomena with polar molecules due to their long range dipole-dipole interactions. In the experiment, loosely bound ultracold KRb molecules, produced by Feshbach \'magneto-association\', are driven into more deeply bound states via Raman transitions. While in these experiments, the comb serves as a stable frequency reference, it is possible also to use the comb directly to drive the molecular dynamics with high efficiency and precision. I will review some of our theoretical work in that context as well. From aaharony at bgu.ac.il Tue Oct 30 10:28:00 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-12 Condensed Matter Seminar Message-ID: <200710300828.KAA98752872@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 12-11-2007 TIME: 11:30am (Mon) PLACE: Physics building room 207 TITLE: Many body phenomena out of equilibrium SPEAKER: Dmitri Gutman, University of Florida, Gainesville ABSTRACT/COMMENTS: When electron tunnels into a quantum solid-state conductor, the tunneling density-of-states, plotted vs. the energy of the tunneling electron, E, exhibits a singularity at E=0. This is known as \"zero-bias anomaly\" (ZBA). This phenomenon is ubiquitous in solid state physics, and is related to a host of important effects ranging from the Coulomb blockade to the Anderson orthogonality catastrophe and the x-ray edge singularity. While some experimental results are available, little has been known about ZBA when the system the electron tunnels into is biased (i.e., is out of equilibrium). I will elaborate on the physics behind ZBA, and report on our analysis of ZBA away from equilibrium. The singular suppression of the density of states ( the result of virtualfluctuations) is smoothed out by real processes leading to the dephasing of quasiparticles. I will show how this is related to the problem of quantum noise and its statistics. In particular I will focus on two cases: (i) Fermi liquid in disordered films (ii) Luttinger liquids in one-dimensional wires. From physics at bgu.ac.il Tue Oct 30 16:00:16 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-10-31 astrophysics seminar Message-ID: <200710301400.QAA99065026@tzin.bgu.ac.il> astrophysics seminar DATE: 31-10-2007 TIME: 12:00 PLACE: Physics building room 207 TITLE: The Rings of Saturn and Uranus SPEAKER: Uri Griv, ABSTRACT/COMMENTS: From nano at bgu.ac.il Wed Oct 31 12:38:23 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-07 nanotechnology workshop Message-ID: <000101c81bac$634106f0$1b0e4884@estinano> Nanotechnology workshop, Wednesday November 7, 12:00 building 29, room 306,Chemistry Department seminar room Title : Quantum light-matter interactions at the single-photon level: single cold atoms coupled to chip-based microresonator Speaker: Dr Barak Dayan Physics Department California Institute of Technlogy USA Abstract: Resonantly confining light to micron-sized high quality microresonators can enhance the electric field associated with even a single photon to a level that is sufficient to coherently excite a single atom. At such conditions, light-matter interactions are not just stronger, but qualitatively different, enabeling, among other things, photon-photon interactions and quantum information processing. In my talk I will describe the first demonstration of such strong coupling between cold atoms and a monolithic microresonator, and present recent experimental results which include demonstration of nonlinearity at the single-photon level, and nonclassical behaviors which violate semi-classical predictions. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071031/6ae8602c/attachment.htm From physics at bgu.ac.il Thu Nov 1 15:57:20 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-05 Particles and Fields Seminar Message-ID: <200711011357.PAA101609866@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 05-11-2007 TIME: 10:00pm (Mon) PLACE: Physics building room 207 TITLE: Wald\'s entropy is equal to a quarter of the Horizen area SPEAKER: Prof. Brustein Ram , Physics Department, BGU. ABSTRACT/COMMENTS: I will review the derivation and properties of the Noether charge entropy proposed by Wald. It will be shown that Wald\'s entropy is equal to a quarter of the horizon area in units of a properly defined effective Newton\'s constant. Some explicit examples will be presented, including Sen\'s model of small black holes. I will briefly discuss the implication of the results and in particular its relevance to the entanglement interpretation of black hole thermodynamics. From band at bgu.ac.il Sun Nov 4 14:03:56 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-28 Physical Chemistry Seminar Message-ID: <200711041203.OAA105335519@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 28-11-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building 29, room 306) TITLE: When Bose-Einstein condensates collide: Density engineering of solitons SPEAKER: Professor Jeff Steinhauer, Technion ABSTRACT/COMMENTS: When two BEC\'s collide with high energy, then the famous standing wave interference pattern is obtained. This interference pattern contains the collisional energy in the form of kinetic energy. For lower collisional energies, the interaction energy becomes significant. In this case, the interference pattern evolves into an array of dark solitons, which contain the collisional energy. We probe the lowest collisional energies, for which a single pair of solitons is produced. This pair of solitons is therefore the low energy version of the standing wave interference pattern. >From an alternative perspective, we produce solitons by engineering the density. This is a complementary technique to previous experiments which produced solitons by engineering the phase. From idobd at bgu.ac.il Sun Nov 4 17:43:10 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-19 Particles and Fields Seminar Message-ID: <200711041543.RAA105653139@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 19-11-2007 TIME: 10:00pm (Mon) PLACE: Physics building (#54) room 207 TITLE: Metastability of R-charged Black Holes SPEAKER: Dr. Daisuke Yamada, Racah Institute of Physics, Hevrew University, Jerusalem ABSTRACT/COMMENTS: The talk is based on a paper with the same title (hep-th/0701254). I explain the relation to AdS/CFT and current efforts to understand the phenomenon in terms of the brane picture. From physics at bgu.ac.il Tue Nov 6 08:27:26 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-07 Seminar in Organic Message-ID: <200711060627.IAA107998015@tzin.bgu.ac.il> Seminar in Organic DATE: 07-11-2007 TIME: 17:00 PLACE: Bldg. 34 Room 110 TITLE: \" BIONIC FIBER-OPTIC BIOSENSORS\" SPEAKER: Prof. Robert Marks, Department for Biotechnology Engineering and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel ABSTRACT/COMMENTS: We are continually challenged with old and new cellular or molecular threats (health, environment and security) and we thrive to replace classic diagnostics in the future with biosensors and biochips . We will discuss our developments in this area, including the BioPen, the first Lab-in-a-Pen that for dispatch. •The development of chemiluminescent fiber-optic immunosensors to Hepatitis C , West Nile , Rift Valley fever , and Ebola viruses, cholera toxin and Ovarian cancer using either silane or electropolymerisation on ITO-coated fiber-optics •The development of bioluminescent fiber-optic whole-cell bioreporter biosensors to gentoxicants , heavy metals and endocrine disrupting compounds . •The development of a chemiluminescent phagocyte-based fiber-optic sensor •The development of nanofluidics and biochip interfaces . From physics at bgu.ac.il Tue Nov 6 09:31:10 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-07 Seminar in Organic - canceled Message-ID: <200711060731.JAA107661042@tzin.bgu.ac.il> Seminar in Organic - canceled DATE: 07-11-2007 TIME: PLACE: TITLE: SPEAKER: , ABSTRACT/COMMENTS: From aaharony at bgu.ac.il Tue Nov 6 12:17:21 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-19 Condensed Matter Seminar Message-ID: <200711061017.MAA107981162@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 19-11-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Molecular structure and elastic properties of cholesterol helical ribbons, self-assembling biological springs SPEAKER: Dr. Boris Khaykovich, MIT, Nuclear Reactor Laboratory, Cambridge, Massachusetts, USA ABSTRACT/COMMENTS: Mesoscopic helical ribbons of two well defined pitch angles viz. 11º and 54º are formed in various multicomponent surfactant-sterol solutions. It was suggested previously that this remarkable stability of the pitch angles results from an underlying crystalline structure of the sterol ribbon strips. Using x-ray diffraction I have indeed observed Bragg reflections from individual ribbons from cholesterol solutions, having 11º pitch angle and deduced the parameters of the unit cell. The crystal structure of these ribbons is similar to that of cholesterol monohydrate, with the important difference that the length of the unit cell perpendicular to the cholesterol layers is tripled. I discuss possible origins for this triplication as well as the connection between the crystalline structure and the geometrical form of the helical ribbons. Motivated by the possibility to use the helical ribbons as mesoscopic springs to measure the forces acting in nano-scale biological systems, I am studying the dependence of elastic modulii of the helices as a function of thickness. These measurements utilize tomographic phase microscopy. I present the results of these studies and compare them with existing models for the elastic modulii of the ribbons. From idobd at bgu.ac.il Wed Nov 7 11:20:00 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-08 SPECIAL HIGH ENERGY SEMINAR Message-ID: <200711070920.LAA109103430@tzin.bgu.ac.il> SPECIAL HIGH ENERGY SEMINAR DATE: 08-11-2007 TIME: 11:30 a.m. Thursday (Tomorrow) PLACE: TBA TITLE: TBA SPEAKER: Prof. Amihay Hanany, ABSTRACT/COMMENTS: The seminar is not at the regular time and place, in order to fit the schedule of the speaker and the physics department. The relevant details will be sent later. From nano at bgu.ac.il Wed Nov 7 12:12:29 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-14 nanotechnology workshop Message-ID: <006601c82126$b488d7c0$1b0e4884@estinano> Nanotechnology workshop, Wednesday November 14, 12:00 building 29, room 306,Chemistry Department seminar room Title : Development and characterization of a new model electrochemical system for analytical measurement of Mycobacteria tuberculosis using a lytic bacteriophage and nanoparticles" Speaker: Dr Miri Yemini Tel Aviv University Abstract: The rapid and reliable detection of pathogenic microorganisms is an important issue for the safety and security of our society. This study focused on the development, characterization, and implementation of a new technology for continuous detection and tracing in real time of extra-low concentrations of Mycobacteria, the causative agent of tuberculosis (TB), with Mycobacteria smegmatis as a model system . Detection was performed by identifying the bacteria using lytic bacteriophages, and then measuring the specific enzymatic activity of the bacteria. The concentration of the product of the enzymatic activity was determined in situ using electrochemical amperometric methods, which enabled the enzymatic activity to be traced in real time. A high detection sensitivity was achieved by using electrodes modified with peptide nanotubes composed of self-assembled biological building blocks. The peptide nanotube-based amperometric biosensor provides a potential new tool for sensitive biosensors and biomolecular diagnostics. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071107/db7a760f/attachment.htm From idobd at bgu.ac.il Wed Nov 7 13:55:19 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-08 SPECIAL HIGH ENERGY PHYSICS SEMINAR Message-ID: <200711071155.NAA109595779@tzin.bgu.ac.il> SPECIAL HIGH ENERGY PHYSICS SEMINAR DATE: 08-11-2007 TIME: 12 P.M. (Tomorrow) PLACE: Room 09 Building 34 TITLE: Tilings, Quivers and Orientifolds SPEAKER: Prof. Amihay Hanany, ABSTRACT/COMMENTS: From idobd at bgu.ac.il Fri Nov 9 09:35:15 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-12 Particles and Fields Seminar Message-ID: <200711090735.JAA111818038@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 12-11-2007 TIME: 10:00pm (Mon) PLACE: Physics building (#54) room 207 TITLE: A model with unavoidable dynamical protection from initial singularity of the curvature SPEAKER: Alexander Kaganovich, BGU ABSTRACT/COMMENTS: A model is presented where the phase plane structure of the inflaton prevents a possibility of an initial singularity of the curvature while its time derivative is singular. This is a realization of a sort of \"sudden\" singularities studied by Barrow on purely kinematic grounds. ? From physics at bgu.ac.il Sun Nov 11 12:34:34 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-15 Physics Colloquium Message-ID: <200711111034.MAA114962644@tzin.bgu.ac.il> Physics Colloquium DATE: 15-11-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: >From nanocrystalline to monocrystalline thin films: microstructure, morphology evolution and epitaxy in chemically deposited semiconductor films SPEAKER: Yuval Golan , Dept. of Materials Engineering, Ben Gurion University ABSTRACT/COMMENTS: Chemical deposition from solution offers a simple and cost-effective route for fabrication of high quality semiconductor thin films, and is useful for deposition of a large variety of semiconductors. Lead selenide and lead sulfide semiconductor thin films deposited using chemical deposition can be obtained in a wide range of morphologies, from nanocrystalline films, through microcrystalline films with columnar grains, to epitaxial monocrystalline films. This is achieved by carefully controlling the active deposition mechanism during growth: The cluster mechanism, in which clusters of the semiconductor material are formed in solution and migrate onto a solid support to form a film, or the ion-by-ion mechanism, in which the reaction occurs (and the film forms) directly on the substrate surface. Strategies for improving material quality and for controlling film orientation will be discussed. In addition to conventional in-house characterization techniques, in-situ techniques such as laser light scattering and synchrotron grazing incidence x-ray diffraction for monitoring film growth and morphology evolution in real time will be highlighted. From aaharony at bgu.ac.il Mon Nov 12 15:07:52 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-26 Condensed Matter Seminar Message-ID: <200711121307.PAA116552871@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 26-11-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Phase switching in a voltage-biased Aharonov-Bohm interferometer SPEAKER: Vadim I. Puller, Department of Physics, Ben-Gurion University of the Negev ABSTRACT/COMMENTS: Recent experiment [Sigrist et al., Phys. Rev. Lett. {\\bf 98}, 036805 (2007)] reported switches between 0 and $\\pi$ in the phase of Aharonov-Bohm oscillations of the two-terminal differential conductance through a two-dot ring with increasing voltage bias. Using a simple model, where one of the dots contains multiple interacting levels, these findings are explained as a result of transport through the interferometer being dominated at different biases by quantum dot levels of different \"parity\" (i.e. the sign of the overlap integral between the dot state and the states in the leads). The redistribution of electron population between different levels with bias leads to the fact that the number of switching events is not necessarily equal to the number of dot levels, in agreement with experiment. For the same reason switching does not always imply that the parity of levels is strictly alternating. Lastly, it is demonstrated that the correlation between the first switching of the phase and the onset of the inelastic cotunneling, as well as the sharp (rather than gradual) change of phase when switching occurs, give reason to think that the present interpretation of the experiment is preferable to the one based on electrostatic AB effect. From Ibar at bgu.ac.il Wed Nov 14 08:36:08 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-20 Lasers Seminar Message-ID: <018a01c82688$a40be5b0$ac574884@ilap> Lasers Seminar DATE: 20-11-2007 TIME: 3:30pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Generation of radially-polarized beams and their applications SPEAKER: Dr. Galina Machavariani, Nonlinear Optics Group, Soreq Nuclear Research Center, 81800 Yavne, Israel ABSTRACT/COMMENTS: We review applications and methods of generation of radially- and azimuthally-polarized beams, and present our new method for generating such beams. We demonstrate an efficient mode converter, which transforms a linearly-polarized Gaussian beam to a radially-or azimuthally-polarized LG(0,1)* beam [1]. The converter is a spatially-variable retarder (SVR), comprised of eight appropriately cut half-wave-plate segments. Such converters are important in the development of high -power lasers for two reasons: to generate radially-polarized beams for aberration-free amplification in rod-based amplifiers, and to generate a nearly diffraction-limited beam by converting the amplified radially-polarized beams back into a Gaussian beam. With our SVR converter, we transformed an Nd:YAG Gaussian beam with M2=1.3 to radially- and azimuthally-polarized (0,1)*LG beams with M2=2.5. The degree of radial polarization, calculated from the measured Stokes parameters, was 96%-98%. Also, we converted a 70W radially-polarized beam with M2=2.6 into a linearly-polarized nearly-Gaussian beam with M2=1.4 [2]. Taking into account power-losses, the beam-brightness was increased by a factor of 2.6. Our SVR is simple, robust, and can be used at high powers. The manufacture of these SVRs was optimized for application to high power lasers, where minimum phase-front distortion and maximum cylindrical- polarization purity is required. [1] G.Machavariani, Y.Lumer, I.Moshe, A.Meir, S.Jackel, Opt.Lett. 32, 1468-1470, (2007). [2] G.Machavariani, S.Jackel, Y.Lumer, I.Moshe, A.Meir, Opt.Lett. 32, 2626-2628, (2007). -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071114/341ce467/attachment.htm From nano at bgu.ac.il Wed Nov 14 13:15:31 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-21 nanotechnology workshop Message-ID: <00eb01c826af$ad67ea60$1b0e4884@estinano> building 29, room 306,Chemistry Department seminar room Title : Science at the edge- Cooperative Molecular Field Effect, the Source for Surprising Electronic and Magnetic Properties of Interfaces Speaker: Ron Naaman Department of Chemical Physics Weizmann Institute Abstract: An electrostatic potential can be created by two dimensional closed packed organized organic layers. This potential can produce similar effects as those produced by the gate in a field effect transistor. We relate to this effect as the cooperative molecular field effect (COMFE). As will be shown, in order to produce a COMFE, specially shaped molecular structures must be formed, characterized by a pseudo-two-dimensional shape, i.e., their length and width are much larger than their thickness. The COMFE can be used for combining the properties of organic molecules with those of semiconductors. One of the manifestations of the COMFE is a new type of magnetism. While most magnetic phenomena are related to spins of unpaired electrons, recently, a new type of magnetism has been identified that is related to interfaces of diamagnetic materials, "interface magnetism". This magnetism was found in organic molecules adsorbed on metals, on carbon surfaces,in HfO2-coated silicon or sapphire and at the silicon- silicon oxide interface This interface magnetism is characterized by being temperature-independent in the range of 0 to 400K, by having high anisotropy, and by having very large magnetic signals per atom on the surface. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071114/527116b6/attachment.htm From nano at bgu.ac.il Wed Nov 14 13:21:24 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-21 nanotechnology workshop Message-ID: <012a01c826b0$81c1cb00$1b0e4884@estinano> Nanotechnology workshop, Wednesday November 21, 12:00 building 29, room 306,Chemistry Department seminar room Title : Science at the edge- Cooperative Molecular Field Effect, the Source for Surprising Electronic and Magnetic Properties of Interfaces Speaker: Ron Naaman Department of Chemical Physics Weizmann Institute Abstract: An electrostatic potential can be created by two dimensional closed packed organized organic layers. This potential can produce similar effects as those produced by the gate in a field effect transistor. We relate to this effect as the cooperative molecular field effect (COMFE). As will be shown, in order to produce a COMFE, specially shaped molecular structures must be formed, characterized by a pseudo-two-dimensional shape, i.e., their length and width are much larger than their thickness. The COMFE can be used for combining the properties of organic molecules with those of semiconductors. One of the manifestations of the COMFE is a new type of magnetism. While most magnetic phenomena are related to spins of unpaired electrons, recently, a new type of magnetism has been identified that is related to interfaces of diamagnetic materials, "interface magnetism". This magnetism was found in organic molecules adsorbed on metals, on carbon surfaces,in HfO2-coated silicon or sapphire and at the silicon- silicon oxide interface This interface magnetism is characterized by being temperature-independent in the range of 0 to 400K, by having high anisotropy, and by having very large magnetic signals per atom on the surface. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071114/264423ee/attachment.htm From physics at bgu.ac.il Thu Nov 15 12:51:57 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-21 Seminar in Organic Message-ID: <200711151051.MAA120717600@tzin.bgu.ac.il> Seminar in Organic DATE: 21-11-2007 TIME: 17:00 PLACE: Bldg. 34 Room 110 TITLE: \"DESIGN, SYNTHESIS AND ELECTROPOLYMERIZATION OF HYBRID PYRROLE BASED COMPOUNDS, FOR USE IN BIOSENSORS\" SPEAKER: Liron Amir, Department of Chemistry, Ben-Gurion University of the Negev ABSTRACT/COMMENTS: Aldehyde and polyethylene glycol substituted polypyrrole materials were synthesized and characterized. We suggest herein a novel method for immobilization of proteins to the surface of an amperometric biosensor, using a polymer containing pendant aldehyde groups (aromatic aldehyde substituted polypyrrole), which can create covalent bonds with proteins. We also present the synthesis of PEG substituted polypyrroles, designed to diminish cell adhesion on the conductive polymer surface. The pyrrole-aldehyde monomer was synthesized, characterized by NMR and MS, and was showed to electropolymerize into a dark poly-pyrrole film, either on mrysl electrodes or ITO deposited slides. The polymer was checked by cyclic voltametry, to show new reduction and oxidation peaks, as compared to polypyrrole. The polypyrrole-aldehyde compound was used to design a new Cholera toxin B biosensor. PEG is known for its protein adsorption and cell adhesion resisting properties. In order to decrease the unspecific binding of proteins and cells, and to create non adhesive conductive surfaces, a new protein repellent polymer- Polyethylene Glycol (PEG) substituted Pyrrole was created. Adhesion test were done by observing the growth of 3T3 cells on electropolymerized ITO slides. From physics at bgu.ac.il Sun Nov 18 09:08:03 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-22 Physics Colloquium Message-ID: <200711180708.JAA123016348@tzin.bgu.ac.il> Physics Colloquium DATE: 22-11-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Physics of cellular shapes SPEAKER: Nir Gov , Department of Chemical Physics Weizmann Institute of Science ABSTRACT/COMMENTS: Cells of a multi-cellular organisms come in a variety of beautiful shapes, according to their different functions inside the body. The building blocks that drive these shape formations are known to be the proteins of the membrane and the cytoskeleton. The cytoskeleton produces forces through actin polymerization and the active motion of molecular motors. These forces deform the membrane of the cell and determine the overall cellular shape, and drive the formation of specialized sub-cellular structures on the cell surface. The biological characterization of these cytoskeletal components is quite advanced, so that it is now possible to attempt a theoretical (mathematical) modeling of these processes in terms of physics and chemistry. There is at present very little understanding of how the cytoskeletal and membranal components are coupled to spontaneously produce the observed variety of cellular shapes,their dynamics and overall life-cycle. We aim to address this gap by using theoretical modeling that is based on general physical principles in order to describe some of the more complex variety of the observed cellular shapes.We present simple analytic models for the self-organization of cellular shapes, from the inner workings of a single membranal deformation to the collective arrangement of hundreds of such units in a complex, dynamic and highly regulated array. From physics at bgu.ac.il Sun Nov 18 09:17:49 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-22 Physics Colloquium Message-ID: <200711180717.JAA123419520@tzin.bgu.ac.il> Physics Colloquium DATE: 22-11-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: Physics of cellular shapes SPEAKER: Dr. Nir Gov , Department of Chemical Physics Weizmann Institute of Science. ABSTRACT/COMMENTS: Cells of a multi-cellular organisms come in a variety of beautiful shapes, according to their different functions inside the body. The building blocks that drive these shape formations are known to be the proteins of the membrane and the cytoskeleton. The cytoskeleton produces forces through actin polymerization and the active motion of molecular motors. These forces deform the membrane of the cell and determine the overall cellular shape, and drive the formation of specialized sub-cellular structures on the cell surface. The biological characterization of these cytoskeletal components is quite advanced, so that it is now possible to attempt a theoretical (mathematical) modeling of these processes in terms of physics and chemistry. There is at present very little understanding of how the cytoskeletal and membranal components are coupled to spontaneously produce the observed variety of cellular shapes, their dynamics and overall life-cycle. We aim to address this gap by using theoretical modeling that is based on general physical principles in order to describe some of the more complex variety of the observed cellular shapes. We present simple analytic models for the self-organization of cellular shapes, from the inner workings of a single membranal deformation to the collective arrangement of hundreds of such units in a complex, dynamic and highly regulated array. From physics at bgu.ac.il Sun Nov 18 10:45:21 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-21 Astrophysics and Cosmology Seminar Message-ID: <200711180845.KAA125076779@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 21-11-2007 TIME: 12:00 noon (Wed) PLACE: Physics building (#54) room 207 TITLE: \"New discoveries from satellites observing the Sun\" SPEAKER: Dr. Leon Ofman , (NASA/GSFC - presently on sabbatical in TAU) ABSTRACT/COMMENTS: Solar magnetic activity determines the conditions in the interplanetary environment, and affects the earth\'s magnetosphere, ionosphere, and upper atmosphere. It can have adverse effects on satellites, and human activity in space, and may be affecting important processes, on Earth such as global warming or cooling. The solar corona has been observed during eclipses for centuries, and spectroscopic observations since 1932 have shown that it reaches millions of degrees (K). However, the exact physical mechanisms that lead to solar activity in the complex magnetized plasma of the sun are still being investigated. The main physical processes believed to play a role are plasma instabilities, turbulence, magnetic reconnection,and dissipation of waves. Recent space based observations of the solar corona with NASA TRACE, RHESSI, and STEREO satellites, and the Japanese Hinode satellite provide new insights into the dynamics of the magnetized plasma in the solar corona at a range of wavelengths from visible to hard x-rays and gamma-rays. The RHESSI satellite provides high energy observations of flares identifying the sites of energy release in the corona. The two satellites of the STEREO mission provide for the first time 3D views of the solar corona. Magnetohydrodynamic waves have been observed in high detail by the TRACE satellite in active regions, and Hinode satellite provides observations of the solar corona and chromosphere at unprecedented resolution from visible to X-ray. I will discuss these observations,and show how they improve our understanding of solar activity. From gideonc at bgu.ac.il Mon Nov 19 11:47:46 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-22 Physics Colloquium - pay attention Message-ID: <200711190947.LAA126363691@tzin.bgu.ac.il> Physics Colloquium - pay attention DATE: 22-11-2007 TIME: 3:30pm (Thu) PLACE: Building 34, room 010 TITLE: This week the colloquium will take place at the seminars room (207) in the physics building. SPEAKER: , ABSTRACT/COMMENTS: From gideonc at bgu.ac.il Tue Nov 20 13:08:49 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-22 Physics Colloquium Message-ID: <200711201108.NAA127998916@tzin.bgu.ac.il> Physics Colloquium DATE: 22-11-2007 TIME: 3:30pm (Thu) PLACE: Building 54, room 207 TITLE: Physics of cellular shapes SPEAKER: Dr. Nir Gov , Department of Chemical Physics, Weizmann Institute of Science ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collq0708_A/Gov.html Refreshments are served at 3:20pm From Ibar at bgu.ac.il Tue Nov 20 17:19:13 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-27 Lasers Seminar Message-ID: <002701c82b88$b56f8370$ac574884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 27-11-2007 TIME: 4:00pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Recent advances in the theory of matter-wave solitons SPEAKER: Dr. Amichay Vardi, Department of Chemistry, Ben Gurion University of the Negev ABSTRACT/COMMENTS: Several recent projects pertaining to the theory of matter-wave solitons in quantum Bose gases, will be reviewed. These include (i) the formation of unisotropic 2D bright solitons in dipolar BECs, (ii) self-consistent calculations of quasi-1D bright soliton dynamics and collapse, and (iii) the generation of non-dispersive dark notches via dynamic, parity-selective filtering in the Tonks-Girardeau gas of impenetrable bosons. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071120/22414804/attachment.htm From nano at bgu.ac.il Wed Nov 21 10:03:10 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-25 nanotechnology workshop- SPECIAL SEMINAR Message-ID: <001e01c82c14$f60f1210$1b0e4884@estinano> Nanotechnology workshop, Sunday November 25, 12:00 The new physics club,building 54, room 207 Title : Structure of DNA dilute and semi-dilute polymer solutions. Speaker: Eyal Shafran BGU -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071121/602d14bf/attachment.htm From nano at bgu.ac.il Wed Nov 21 10:10:23 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-25 nanotechnology workshop- SPECIAL SEMINAR-CORRECTION Message-ID: <003401c82c15$f766e470$1b0e4884@estinano> ----- Original Message ----- From: Nano To: nano Sent: Wednesday, November 21, 2007 10:03 AM Subject: 2007-11-25 nanotechnology workshop- SPECIAL SEMINAR Nanotechnology workshop, Sunday November 25, 14:00 The new physics club,building 54, room 207 Title : Structure of DNA dilute and semi-dilute polymer solutions. Speaker: Eyal Shafran BGU -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071121/225300d3/attachment.htm From nano at bgu.ac.il Wed Nov 21 12:36:50 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-28 nanotechnology workshop Message-ID: <00a201c82c2a$6ca37780$1b0e4884@estinano> Nanotechnology workshop, Wednesday November 28, 12:00 building 29, room 306,Chemistry Department seminar room Title : Formulation, Characterization and Applications of Microemulsions Speaker: Monzer Fanun Faculty of Science and Technology Al-Quds University East Jerusalem Abstract: Microemulsions are stable isotropic dispersions of at least three components: a polar and non-polar liquid phases usually (water or brine and oil), and surfactant(s), which on a microscopic level, form a film separating the two incompatible solvents into two sub-phases. Their size is from 1 to 100 nm. Their physicochemical properties which include thermodynamic stability, high solubilization power, low interfacial tensions, transparency, and low viscosity are of great importance. Microemulsions find applications in biotechnology as a media for enzymatic reactions, in pharmacy as carriers of drugs, in foods, as solubilizers of flavors, aromas, colors and vitamins, in the synthesis of nanoparticles of advanced materials such as superconductors, in enhanced oil recovery and in detergency processes. In this presentation we will talk about our research activities on microemulsions conducted at Al-Quds University. Our studies on microemulsions include the formulation of new systems for industrial applications based on mixed nonionic surfactants and biocompatible oils. The formulated systems characterization that include the study of the transport properties by electrical conductivity and dynamic viscosity, diffusion properties by nuclear magnetic resonance and dynamic light scattering, volumetric properties by measuring the density and the ultrasonic velocity, thermal properties by measuring the specific heat, thermal conductivity and thermal diffusivity, microstructure by small angle X-ray scattering and small angle neutron scattering, building models for the prediction of the structural parameters (i.e. aggregation number, core radius). The formulated microemulsions are intended to be used in the formulation of new drug delivery systems, in the formulation of new functional foods, in the synthesis of nanoparticles and in organometallic catalysis. The relationships between the properties of the formulated microemulsions and their efficiency in the intended applications are also studied. Examples of studied systems will be presented. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071121/5e764384/attachment.htm From aaharony at bgu.ac.il Wed Nov 21 17:31:00 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-03 Condensed Matter Seminar Message-ID: <200711211531.RAA130130072@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 03-12-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Fluctuation relations and coarse-graining SPEAKER: Saar Rahav, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742 ABSTRACT/COMMENTS: : The understanding of systems far from equilibrium remains a central challenge in statistical mechanics. In recent years a number of theoretical predictions, known collectively as fluctuation relations, have been derived and in some cases confirmed experimentally. These predictions, which remain valid far from equilibrium, are related to symmetries of the system, such as time reversal. While fluctuation relations pertain to the microscopic dynamics of the system in question, in practice the detailed knowledge of such dynamics is not always available. We consider the application of fluctuation relations to the dynamics of coarse-grained systems, as might arise in a hypothetical experiment with a low resolution apparatus. We find that separation of time scales leads to a non-trivial fluctuation relation, which is satisfied by the coarse-grained dynamics. From physics at bgu.ac.il Thu Nov 22 15:01:21 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-28 Physical Chemistry Seminar Message-ID: <200711221301.PAA131108681@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 28-11-2007 TIME: 16:00 PLACE: Bldg. 29, Room 306 (Seminar Room) TITLE: When Bose-Einstein condensates collide: Density engineering of solitons SPEAKER: Professor Jeff Steinhauer, Technion ABSTRACT/COMMENTS: When two BEC\'s collide with high energy, then the famous standing wave interference pattern is obtained. This interference pattern contains the collisional energy in the form of kinetic energy. For lower collisional energies, the interaction energy becomes significant. In this case, the interference pattern evolves into an array of dark solitons, which contain the collisional energy. We probe the lowest collisional energies, for which a single pair of solitons is produced. This pair of solitons is therefore the low energy version of the standing wave interference pattern. From an alternative perspective, we produce solitons by engineering the density. This is a complementary technique to previous experiments which produced solitons by engineering the phase. From physics at bgu.ac.il Thu Nov 22 15:07:14 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-28 Seminar in Organic Message-ID: <200711221307.PAA130428231@tzin.bgu.ac.il> Seminar in Organic DATE: 28-11-2007 TIME: 17:00 PLACE: Bldg. 34 Room 110 TITLE: A Thermally Switchable Latent Ruthenium Olefin Metathesis Catalyst SPEAKER: Dr. Gabriel Lemcoff, Department of Chemistry Negev, Ben-Gurion University of the Negev ABSTRACT/COMMENTS: Over the past decade olefin metathesis reaction has become one of the most powerful tools for C-C bond formation in organic synthesis and polymer science. Since the development of active, well-defined molybdenum and ruthenium-based catalysts, extensive research efforts have been done to tune the catalysts stability, activity and selectivity by introducing a wide variety of ligands to the metal shells.Yet another fascinating goal to be met concerning catalysts is the ability to control their activities either by physical or chemical means. Indeed, recently some success has been reached in developing thermally activated ring opening metathesis polymerization (ROMP) catalysts based on chelates formed via nitrogen donor atoms. We envisioned that a stronger ligation of the ruthenium metal by a sulfur atom instead of the typically used oxygen or nitrogen chelates would allow us to prepare an extremely stable catalyst active only when heated. Our results show that single atom exchange of oxygen by sulfur provides an extremely stable olefin metathesis catalyst which is completely inert to RCM reactions at room temperature and is only active at high temperatures. This behavior was also shown to be totally reversible. From physics at bgu.ac.il Sun Nov 25 13:00:43 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-29 Physics Colloquium Message-ID: <200711251100.NAA135667715@tzin.bgu.ac.il> Physics Colloquium DATE: 29-11-2007 TIME: 3:30pm (Thu) PLACE: Building 54,Room 207- * Notice the permanent change of room TITLE: Medium-induced interactions under confinement SPEAKER: Prof. Haim Diamant , School of Chemistry, Tel Aviv University. ABSTRACT/COMMENTS: Particles embedded in a medium experience effective interactions as they obstruct the response of the mediumto perturbations. Prime examples are the dispersion (van der Waals) interaction, arising from the electrodynamic response of the medium, and the hydrodynamic interaction - velocity correlations induced by medium flow. Confining boundaries may have a dramatic effect on such medium-induced interactions. We shall review recent experimental and theoretical findings, as well as outstanding puzzles, concerning these strong confinement effects. From Ibar at bgu.ac.il Mon Nov 26 11:41:34 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-27 Lasers Seminar Message-ID: <012301c83010$88db1bd0$ac574884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 27-11-2007 TIME: 3:30pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Recent advances in the theory of matter-wave solitons SPEAKER: Dr. Amichay Vardi, Department of Chemistry, Ben Gurion University of the Negev ABSTRACT/COMMENTS: Several recent projects pertaining to the theory of matter-wave solitons in quantum Bose gases, will be reviewed. These include (i) the formation of unisotropic 2D bright solitons in dipolar BECs, (ii) self-consistent calculations of quasi-1D bright soliton dynamics and collapse, and (iii) the generation of non-dispersive dark notches via dynamic, parity-selective filtering in the Tonks-Girardeau gas of impenetrable bosons. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071126/a4049121/attachment.htm From physics at bgu.ac.il Mon Nov 26 14:21:27 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-11-28 Astrophysics and Cosmology Seminar Message-ID: <200711261221.OAA137377152@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 28-11-2007 TIME: 12:00 noon (Wed) PLACE: Physics building (#54) room 207 TITLE: Possible manifestations of Space Weather influence on wheat market in past on in present time SPEAKER: Dr. Lev Pustil\'nik , Israel Space Weather and Cosmic RAy Ceneter, Tel Aviv University ABSTRACT/COMMENTS: From band at bgu.ac.il Mon Nov 26 15:50:27 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-27 Physical Chemistry Seminar Message-ID: <200711261350.PAA137558768@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 27-12-2007 TIME: 4:00 P.M. (Wed) PLACE: Chemistry club (Building #29, room 306) TITLE: Detection of acceleration radiation in a Bose-Einstein condensate SPEAKER: Professor Alexander Retzker, Imperial College London ABSTRACT/COMMENTS: We propose and study methods for detecting the Unruh effect in a Bose-Einstein condensate. The Bogoliubov vacuum of a Bose-Einstein condensate is used here to simulate a scalar field-theory, and accelerated atom dots or optical lattices as means for detecting phonon radiation due to acceleration effects. We study Unruh\'s effect for linear acceleration and circular acceleration. In particular, we study the dispersive effects of the Bogoliubov spectrum on the ideal case of exact thermalization. Our results suggest that Unruh\'s acceleration radiation can be tested using current accessible experimental methods. From band at bgu.ac.il Tue Nov 27 12:25:12 2007 From: band at bgu.ac.il (band@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-26 Physical Chemistry Seminar Message-ID: <200711271025.MAA138433892@tzin.bgu.ac.il> Physical Chemistry Seminar DATE: 26-12-2007 TIME: 4:00 P.M. (Wed) (Date correction) PLACE: Chemistry club (Building #29, room 306) TITLE: Detection of acceleration radiation in a Bose-Einstein condensate SPEAKER: Professor Alexander Retzker, Imperial College London ABSTRACT/COMMENTS: We propose and study methods for detecting the Unruh effect in a Bose-Einstein condensate. The Bogoliubov vacuum of a Bose-Einstein condensate is used here to simulate a scalar field-theory, and accelerated atom dots or optical lattices as means for detecting phonon radiation due to acceleration effects. We study Unruh\'s effect for linear acceleration and circular acceleration. In particular, we study the dispersive effects of the Bogoliubov spectrum on the ideal case of exact thermalization. Our results suggest that Unruh\'s acceleration radiation can be tested using current accessible experimental methods. From idobd at bgu.ac.il Tue Nov 27 12:45:13 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-03 Particles and Fields Seminar Message-ID: <200711271045.MAA137922605@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 03-12-2007 TIME: 10:00pm (Mon) PLACE: Physics building (#54) room 207 TITLE: Modeling the Gregory-Laflamme decay by fluids SPEAKER: Umpei Miyamoto , Racah Institute of Physics, Hebrew University of Jerusalem ABSTRACT/COMMENTS: The close similarity between the Gregory-Laflamme instability for extended horizons and the Rayliegh-Plateau instability for extended fluids held by surface tension has been known (Cardoso & Dias PRL2006). First, I review what we know about the final fate of the Gregory-Laflamme instability. Then, I propose a geometrical action formalism of a fluid/membrane, modeling the in-homogeneous black strings and localized black holes in spacetimes with one compact direction. I show a \"phase diagram\" of fluid configurations, by which we can \"confirm\" the critical dimension known on the gravity side (Sorkin PRL2004) and discuss the final fate of the Gregory-Laflamme decay in any dimension. From Ibar at bgu.ac.il Tue Nov 27 16:54:41 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-04 Lasers Seminar Message-ID: <02c501c83105$708fd110$ac574884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 04-12-2007 TIME: 3:30pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Nonlinear collapse dynamics of intense laser beams SPEAKER: Dr. Amiel A. Ishaaya, Dept. of Electrical and Computer Engineering, Ben Gurion University of the Negev ABSTRACT/COMMENTS: Over the past decade, with the advent of high peak power ultra-short pulsed lasers, understanding the nonlinear propagation of the pulses from these systems has become increasingly important for various applications, such as LIDAR and remote sensing. In this talk I will present recent theoretical and experimental results of self focusing and collapse of intense optical beams, revealing a remarkable richness of nonlinear phenomena. This includes self focusing of beams of various spatial distributions, such as super-Gaussian, phase vortex, and necklace beams, along with the mutual collapse dynamics and interactions between several spatially separated beams. Our results shed light on the basic dynamics of self focused beams and provide a possible route to controlling the nonlinear propagation of such high-power laser pulses. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071127/1edd3c07/attachment.htm From aaharony at bgu.ac.il Wed Nov 28 10:05:16 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-10 Condensed Matter Seminar Message-ID: <200711280805.KAA245105@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 10-12-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Stability and roughness of crack paths in 2D heterogeneous brittle materials SPEAKER: Dr. Eytan Katzav, Ecole Normale, Paris, France ABSTRACT/COMMENTS: I will present a recent study on the stability of propagating cracks in heterogeneous two-dimensional brittle materials and on the roughness of the surfaces created by this irreversible process. A stochastic model describing the propagation of the crack tip based on an elastostatic description of crack growth in the framework of linear elastic fracture mechanics will be introduced. The model recovers the stability of straight cracks and allows for the study of the roughening of fracture surfaces. We show that in a certain limit, the problem becomes exactly solvable and yields analytic predictions for the power spectrum of the paths. This result suggests a surprising alternative to the conventional power law analysis often used in the analysis of experimental data and thus calls for a revised interpretation of the experimental results. From nano at bgu.ac.il Wed Nov 28 12:42:31 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-05 nanotechnology workshop Message-ID: <004f01c831ab$60ff1e80$1b0e4884@estinano> Nanotechnology workshop, Wednesday December 5, 12:00 building 29, room 306,Chemistry Department seminar room Title : Chiral surfaces:preparation, characterization and applications. Speaker: Dr. Yitzhak Mastai chemistry Department Bar Ilan University Abstract: Chiral surfaces provide effective environments for chiral molecular discrimination in both natural and industrial contexts. Chiral surfaces have received attention for their potential applications in the chiral selection and purification of pharmaceuticals and other molecular products. In this lecture we will describe our approaches to the synthesis and use of chiral surfaces as chiral resolving auxiliaries in crystallization of enantiomers. The underlying philosophy of our work is to use enantiospecific chiral surfaces during crystallization of racemic in order to achieve chiral separation by crystallization. This will be illustrated with reference to our recent work on: (a) the use of chiral self-assembled monolayers1,2 and (b) selective chiral crystallization of racemic compounds onto chiral polymeric microparticles.3,4 Finally we will also describe a novel method that is capable to recognize chirality of surfaces with nano scale resolution based on the optical properties of chiral surfaces. We shall demonstrate that polarized near field scanning optical microscopy (NSOM)5 can be utilized to measure chirality of surfaces. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071128/f87be070/attachment.htm From physics at bgu.ac.il Thu Nov 29 12:54:04 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-05 Seminar in Organic Message-ID: <200711291054.MAA1887221@tzin.bgu.ac.il> Seminar in Organic DATE: 05-12-2007 TIME: 17:00 PLACE: Bldg. 34 Room 110 TITLE: Kinetic research and process optimization in industrial chemistry SPEAKER: Michael Grabarnick, Makhteshim – Agan Industry ABSTRACT/COMMENTS: Chemical research in industrial laboratories deals with two main subjects - development of new technological processes and improvement of the existing ones. In both cases, the aim is to synthesize the desired compound with minimal cost with the highest possible safety measures and without negative ecological impact. To achieve these targets, an understanding of the reaction mechanism is needed. The most important parameters of the reaction have to be distinguished and optimized. During the presentation two different research methods will be discussed. The first one is kinetic investigation of the main and side reactions, modeling of the chemical process on the base of available software (DynoChem in our case) and choice of the process conditions using computer simulations. The second method is optimization by the Design of Experiment (DOE), calculating of the linear or nonlinear model of the process and using these results for better understanding of the reaction mechanism and the correct process conditions. Comparison of these two methods, using the real examples from the recent Makhteshim’s research, will be presented. The choice of the preferable research method will be recommended. From physics at bgu.ac.il Sun Dec 2 14:32:41 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-06 Physics Colloquium Message-ID: <200712021232.OAA5345713@tzin.bgu.ac.il> Physics Colloquium DATE: 06-12-2007 TIME: 3:30pm (Thu) PLACE: Physics building (#54) room 207 TITLE: Interacting molecular sensors in bacteria SPEAKER: Dr. Ady Vaknin, Racah Institute of Physics Hebrew University, Jerusalem ABSTRACT/COMMENTS: Bacterial cells constantly monitor the environment by utilizing a variety of molecular sensors that span their membrane and relay external signals into the cell. A notable example are the \'chemo-receptors\' that navigate the cells towards regions in the environment that they deem favorable. These sensors were recently shown to form two-dimensional array encored to the cell membrane. Such clustering is generally thought to promote physical coupling between sensors and thereby collective responses and signal modulation. Using fluorescence-microscopy we study these sensors in real time and in living cells, aiming at understanding how they physically function, response, and interact. From physics at bgu.ac.il Mon Dec 3 09:19:57 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-05 Astrophysics and Cosmology Seminar Message-ID: <200712030719.JAA7670743@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 05-12-2007 TIME: 12:00 noon (Wed) PLACE: Physics building (#54) room 207 TITLE: Solar wind interaction with non-magnetized planets SPEAKER: Prof. Michael Gedalin, ABSTRACT/COMMENTS: From physics at bgu.ac.il Tue Dec 4 10:59:10 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-05 Astrophysics and Cosmology Seminar Message-ID: <200712040859.KAA9371570@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 05-12-2007 TIME: 12:00 noon (Wed) PLACE: Physics building (#54) room 207 TITLE: FULLY DEVELOPED TURBULENCE IN ACCRETION DISCS OF BINARY STARS: TURBULENT VISCOSITY COEFFICIENT AND POWER SPECTRUM SPEAKER: Prof. Alexei Fridman, Head of Department of Institute of Astronomy RAS (INASAN). Head of Department of Moscow Institute of Physics and Technology. Professor of Moscow University, Visiting Professor of Tel-Aviv University. ABSTRACT/COMMENTS: We show the existence of the \"spiral-vortex\" structure in an accretion disc in close binary stars (CBS) by using 3D numerical simulation. This structure is not related to the tidal influence of the companion star. It is density wave containing a one-armed spiral and anticyclone vortex, centered at the co-rotation circle. From Ibar at bgu.ac.il Tue Dec 4 17:02:16 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-11 Lasers Seminar Message-ID: <01f301c83686$a8ef9410$ac574884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 11-12-2007 TIME: 3:30pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Towards colloidal-based quantum dot lasers SPEAKER: Dr. Dan Oron, Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, 76100 ABSTRACT/COMMENTS: Colloidal quantum dots are promising fluorophores due to their tremendous photostability and broad size tuning range. As such, they seem to be good candidates for optical gain applications. However, fundamental loss processes due to exciton-exciton interactions can significantly limit the applicability for gain applications of "simple" quantum dots. The possible routes to overcome this and prospects for colloidal-based gain devices will be discussed. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071204/f3185de6/attachment.htm From nano at bgu.ac.il Wed Dec 5 10:11:20 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:27 2009 Subject: [Phys-seminars] 2007-12-11 SPECIAL SEMINAR Message-ID: <006301c83716$6afe0660$1b0e4884@estinano> SPECIAL SEMINAR , Tuesday 11/12, 15:00 Auditorium, hitech (Alon) building, bldg 37, room 202 Title : Is there a length scale in polymer toughening ? Speaker: Prof. Ludwik Leibler ESPCI, Paris Abstract: Dispersing small micron-sized particles can remarkably change the fracture of semi-crystalline polymers from brittle to ductile. Such toughening technique is widely used in today?s polymer industry and has stimulated abundant research efforts. Still, predicting whether a given particle dispersion induces ductility or not is a delicate and challenging problem. I will discuss some relevant experimental aspects of toughening and propose a model that considers the physical approaches to fracture in heterogeneous media and explains the physical origin of a critical matrix confinement necessary to obtain a ductile behavior. Agreement with experimental data is surprisingly good and reveals unexpected dependences on particle size. Moreover, our model can predict effects of temperature or crystalline organization on toughening efficiency and gives simple yet realistic guides that should help designing appropriate toughened systems taking into account the dispersion size, the processing conditions as well as the potential loadings. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071205/b484efec/attachment.htm From aaharony at bgu.ac.il Wed Dec 5 12:18:52 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-17 Condensed Matter Seminar Message-ID: <200712051018.MAA10980393@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 17-12-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Fermi arcs in phase fluctuating d-wave superconductors SPEAKER: Ehud Altman, Weizmann Institute of Science, Rehovot, Israel ABSTRACT/COMMENTS: One of the most puzzling aspects of the high Tc superconductors is the appearance of Fermi arcs in the normal state of the underdoped cuprate materials. These are loci of low energy excitations covering part of the fermi surface, that suddenly appear above Tc instead of the nodal quasiparticles. Based on a semiclassical theory, we argue that partial Fermi surfaces arise naturally in a d-wave superconductor that is destroyed by thermal phase fluctuations. Specifically, we show that the electron spectral function develops a square root singularity at low frequencies for wave-vectors positioned on the bare Fermi surface. We predict a temperature dependence of the arc length that can partially account for results of recent angle resolved photo emission (ARPES) experiments. From physics at bgu.ac.il Thu Dec 6 12:32:11 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-12 Astrophysics and Cosmology Seminar Message-ID: <200712061032.MAA12372960@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 12-12-2007 TIME: 12:00 noon (Wed) PLACE: Physics building (#54) room 207 TITLE: Coherent large-scale structures in turbulent convection: observations, experiments and theory SPEAKER: I. Rogachevskii, Department of Mechanical Engineering Ben-Gurion University of the Negev ABSTRACT/COMMENTS: A review of our theoretical and experimental studies of coherent large-scale structures in turbulent convection is presented. A new mean-field theory of turbulent convection is developed. In a shear-free turbulent convection the theory predicts the convective wind instability which causes formation of large-scale coherent fluid motions in the form of cells. In the presence of shear, the theory predicts another type of instability, which causes formation of large-scale coherent structures in the form of rolls and generation of convective-shear waves propagating perpendicular to the convective rolls. In the experimental study of turbulent convection we use Particle Image Velocimetry to determine the turbulent and mean velocity fields, and a specially designed temperature probe with twelve sensitive thermocouples to measure the temperature field. The hysteresis phenomenon in turbulent convection was found by varying the temperature difference between the bottom and upper walls of the chamber. The hysteresis loop comprises the one-cell and two-cells flow patterns while the aspect ratio is kept constant. The developed theory of semi-organized structures in turbulent convection is in agreement with the experimental observations. The observed coherent structures are superimposed on a small-scale turbulent convection. The redistribution of the heat flux plays a crucial role in the formation of coherent large-scale circulations in turbulent convection. Predictions of the developed theory are in a good agreement with the observed coherent structures in the atmospheric turbulent convection. Astrophysical applications of the obtained results are also discussed From physics at bgu.ac.il Thu Dec 6 12:44:58 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-12 Seminar in Organic Message-ID: <200712061044.MAA12511492@tzin.bgu.ac.il> Seminar in Organic DATE: 12-12-2007 TIME: 17:00 PLACE: Bldg. 34 Room 110 TITLE: New Insights into the Old Boring Oxidative Addition – Reductive Elimination Reactions SPEAKER: Arkadi Vigalok , School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences,Tel Aviv University ABSTRACT/COMMENTS: Oxidative addition and reductive elimination reactions are two pillars of organometallic chemistry. Although square planar late transition metal complexes are considered the most well-studied systems with regard to the above processes, I will argue that the mechanistic pathways in these systems are far from fully understood. We recently reported that the addition of the fluorinating reagent XeF2 to Pt(II) diaryl complexes, bearing the chelating phosphine ligands, instantaneously produced the difluoro Pt(II) complexes together with the product of C-C reductive elimination. The same reaction with the Pt(II) complexes bearing monodentate phosphine ligands produced exceptionally stable Pt(IV) difluoro complexes. This lead us to consider that, in the former case, the C-C reductive elimination might have occurred during the oxidative addition reaction, at a step prior to the formation of the Pt(IV) difluoro complexes. In my talk, I will present our latest, unpublished results on the mechanistic studies of the oxidative addition – reductive elimination sequence in d8 metal systems, with an emphasis on the highly unusual reductive elimination of carbon-halogen bonds. From physics at bgu.ac.il Sun Dec 9 08:43:52 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-13 Physics Colloquium Message-ID: <200712090643.IAA16701681@tzin.bgu.ac.il> Physics Colloquium DATE: 13-12-2007 TIME: 3:30pm (Thu) PLACE: Physics building (#54) room 207 TITLE: Interference of one and two particles SPEAKER: Prof. Moty Heiblum , Department of Condensed Matter Physics Weizmann Institute of Science ABSTRACT/COMMENTS: I will describe first order interference of a single particle and a second order interference between two indistinguishable particles. Two types of interferometers will be utilized to perform these measurements; both utilizing edge channel transport in two-dimensional-electron-gas under a strong magnetic field. From nano at bgu.ac.il Mon Dec 10 11:07:53 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-19 nanotechnology workshop Message-ID: <004801c83b0c$2560db10$1b0e4884@estinano> Nanotechnology workshop, Wednesday December 19, 12:00 building 29, room 306,Chemistry Department seminar room Title : ACTIVE SELF-ORGANIZATION OF MYOSIN II MOTORS AND ACTIN FILAMENTS Speaker: Anne Barnheim-Groswasser Dept. of Chemical Engineering BGU Abstract: Living cells have remarkable mechanical properties. In addition to passive response to mechanical stresses, eukaryotic cells are also able to actively change their shapes and to generate forces and movement in response to external signals. These properties are mainly attributed to the mechanical and dynamical properties of the cell cytoskeleton ? an active network of filamentous proteins such as F-actin and microtubules (MTs). From a biological point of view the cytoskeleton plays a key role in many cellular processes such as mitosis, motility, and adhesion. The aptitude to execute such a diversity of tasks relies on the cytoskeleton?s ability to self-organize and to constantly remodel itself due to the action molecular motor proteins. One important class of motor proteins are Myosin II molecular motors. These motors control the dynamic self-organization of various cytoskeletal structures such as the contractile ring and stress fibers. The study of the action of individual components involved in the cytoskeleton active remodeling is too complex to be studied in vivo. Simplified in vitro systems provide a controlled environment for studying systematically the role of constituent proteins. Here we report on an in vitro experimental study of the active self-organization of actin by myosin II motor proteins in bulk. The active patterns shown here and their dynamics of formation involve totally different mechanisms compared to passive systems (not including motor proteins). Our findings show a wide range of active processes and dynamics, many of them not predicted by current theoretical models. This system is able to generate active networks, asters and even rings depending on myosin II and bundling proteins concentrations. Unexpectedly, we found that the addition of passive bundling proteins (i.e., fascin) is indispensable for pattern formation. We show that the nature of the reorganization process is complex and can generate metastable patterns at short time scales which can further transform to their final steady state structure as time evolves. The time scales of these transformations can range from minutes to hours depending on the type of the pattern. In addition, we find that the motors generate the formation of the patterns, but above a critical concentration they can also destroy them or even inhibit the polymerization and bundling of actin filaments. Our results therefore demonstrate that one possible way to tune the assembly or disassembly of these structures can be done just by changing the concentration/activity of myosin II motors. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071210/201e395d/attachment.htm From physics at bgu.ac.il Mon Dec 10 13:45:36 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-13 Physics Colloquium Message-ID: <200712101145.NAA18554693@tzin.bgu.ac.il> Physics Colloquium DATE: 13-12-2007 TIME: 3:30pm (Thu) PLACE: Physics building (#54) room 207 TITLE: Single particle interference away from the linear regime SPEAKER: Prof. Moty Heiblum , Department of Condensed Matter Physics Weizmann Institute of Science ABSTRACT/COMMENTS: Single particle interference is a well understood phenomenon. Interferometers in the linear regime were used to determine coherence length, to measure phase evolution in coherent systems,and to study statistics of particles. However, away from the linear regime, we found a peculiar behavior. The interference vanished for certain energies, corresponding approximately to the presence of a small integer number of electrons in the interferometer. Extensive measurements with an \'electronic mach zehnder interferometer\' allowed us to show that the unexpected behavior results from electron-electron interactions, but in a rather complicated way, which is yet not fully understood. From aaharony at bgu.ac.il Tue Dec 11 10:42:11 2007 From: aaharony at bgu.ac.il (aaharony@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-24 Condensed Matter Seminar Message-ID: <200712110842.KAA19955964@tzin.bgu.ac.il> Condensed Matter Seminar DATE: 24-12-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: A PARADIGM CALLED MAGNETISM SPEAKER: Professor Sushanta Dattagupta , Director, Indian Institute of Science Education and Research, Kolkata, India ABSTRACT/COMMENTS: THIS IS A SPECIAL SEMINAR, FROM 11:30 TO 13:00. Magnetism, though a very old subject, has continued to influence the developments and concepts in other subjects, not just in Condensed Matter Physics but in other areas of Physics as well. Starting from the ideas of broken symmetry, scaling, critical phenomena, etc. that first appeared in Magnetism, I will dwell into more modern topics such as Quantum Phase Transitions, Glass Transitions, Relaxation and Quantum Dissipation. From Ibar at bgu.ac.il Tue Dec 11 16:50:16 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-18 Lasers Seminar Message-ID: <00fb01c83c05$24f70290$ac574884@ilap> ANNOUNCEMENT==> Lasers Seminar DATE: 18-12-2007 TIME: 3:30pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Autodyne Lidar: Remote sensing and Detection of Hostile Gases SPEAKER: Dr. Gennady Koganov, Department of Physics, Ben Gurion University of the Negev ABSTRACT/COMMENTS: The fact that lasers exhibit the autodyne effect commonly found in self-excited oscillation systems, makes them feasible for sensing applications not only as light sources, but also as high-sensitivity return signal detectors. The results obtained from theoretical and experimental studies have shown that the use of a laser to detect its return signals makes it possible to perform high-sensitivity low-power signal detection. It also makes possible to retrieve a set of optical properties of a remote ?reflector? and the characteristics of its motion from a single measurement. This makes an autodyne lidar a promising means for remote sensing of the atmosphere and earth surface. The general principles of autodyning and some applications of autodyne lidars will be discussed. Analytical approach that allows one to obtain approximate formulae expressing the parameters of the atmosphere through the quantities measured in experiment will be presented. Finally, a scheme of autodyne lidar with multiple external mirrors will be described. The usage of such schemes allows to detect and locate the concentration of hostile gases between any pair of neighboring remote mirrors. -------------------------------------------------------------------------------- _______________________________________________ Physics Department Homepage: http://www.bgu.ac.il/physics/ Campus map and directions: http://www.bgu.ac.il/physics/directions.html More information on [Phys-seminars]: http://www.bgu.ac.il/physics/phys_boards.html Subscription and unsubscription: http://lists.bgu.ac.il/mailman/listinfo/phys-seminars -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071211/c073d411/attachment.htm From idobd at bgu.ac.il Wed Dec 12 11:49:08 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-17 Particles and Fields Seminar Message-ID: <200712120949.LAA21598275@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 17-12-2007 TIME: 10:00am (Mon) PLACE: Physics building (#54) room 207 TITLE: Generation of primordial cosmological density inhomogeneities with scale invariant power spectrum during the standard radiation dominated expansion of the universe SPEAKER: David Oaknin, Rafael ABSTRACT/COMMENTS: The expansion/contraction of a bubble of gas of radius R(t) immersed in an incompressible fluid generates throughout the infinite 3D space round it a radial flow v(r,t) ~ (dR(t)/dt)/r^2. This flow is set at any time by the velocity of the bubble surface at that same instant and, thus, it brings forth equal time correlations over infinitely long distances. These correlations are imposed by global conservation laws and, therefore, do not violate causality. In particular, this incompressible flow produces equal time kinetic energy density anticorrelations that decrease as e(r) ~ -1/r^4. These energy density inhomogeneities have scale invariant power spectrum P(k) ~ k in the range of very small wavenumbers. We discuss this mechanisms as a toy model of physical processes that could operate in the cosmic plasma during the radiation dominated expansion of the universe to generate scale invariant primordial cosmological structures at the time of decoupling. From gideonc at bgu.ac.il Wed Dec 12 14:13:51 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-13 Physics Colloquium - Cancellation Message-ID: <200712121213.OAA21546326@tzin.bgu.ac.il> Physics Colloquium - Cancellation DATE: 13-12-2007 TIME: 3:30pm (Thu) PLACE: Physics building (#54) room 207 TITLE: The Colloquium is cancelled this week due to sickness of the lecturer. SPEAKER: , ABSTRACT/COMMENTS: From physics at bgu.ac.il Sun Dec 16 09:25:10 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-20 Physics Colloquium Message-ID: <200712160725.JAA27381355@tzin.bgu.ac.il> Physics Colloquium DATE: 20-12-2007 TIME: 3:30pm (Thu) PLACE: Physics building (#54) room 207 TITLE: Space Weather: What we understand and what we do not SPEAKER: Dr. Leon Ofman , NASA/GSFC (now on sabbatical in TAU) ABSTRACT/COMMENTS: Space weather describes the conditions in space that affect Earth and its technological systems. Our space weather is a consequence of the behavior of the sun, the nature of Earth\'s magnetic field, and our location in the solar system. Solar magnetic activity varies on a quasi-regular cycle of 11 years, and 2007 is near the minimum. During solar activity minima, fast wind stream can occupy large fraction of the heliosphere. During peaks of solar activity frequent solar storms caused by coronal mass ejections (CME\'s) can impact the Earth\'s magnetosphere, and adversely affect human technology in space and communications on earth. One of the most important challenges of solar physics research is to develop space weather prediction, and to understand the impact of dynamical processes at the Sun on the heliosphere, the Earth\'s magnetosphere, and ionosphere. I will discuss recent advances in our understandind of the physical processes on the Sun and implications for what is happening in the near Earth space. From nano at bgu.ac.il Mon Dec 17 09:57:19 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-19 nanotechnology workshop Message-ID: <003901c84082$72a7e0f0$1b0e4884@estinano> ----- Original Message ----- From: Nano To: nano Sent: Monday, December 10, 2007 11:07 AM Subject: 2007-12-19 nanotechnology workshop Nanotechnology workshop, Wednesday December 19, 12:00 building 29, room 306,Chemistry Department seminar room Title : ACTIVE SELF-ORGANIZATION OF MYOSIN II MOTORS AND ACTIN FILAMENTS Speaker: Anne Barnheim-Groswasser Dept. of Chemical Engineering BGU Abstract: Living cells have remarkable mechanical properties. In addition to passive response to mechanical stresses, eukaryotic cells are also able to actively change their shapes and to generate forces and movement in response to external signals. These properties are mainly attributed to the mechanical and dynamical properties of the cell cytoskeleton ? an active network of filamentous proteins such as F-actin and microtubules (MTs). From a biological point of view the cytoskeleton plays a key role in many cellular processes such as mitosis, motility, and adhesion. The aptitude to execute such a diversity of tasks relies on the cytoskeleton?s ability to self-organize and to constantly remodel itself due to the action molecular motor proteins. One important class of motor proteins are Myosin II molecular motors. These motors control the dynamic self-organization of various cytoskeletal structures such as the contractile ring and stress fibers. The study of the action of individual components involved in the cytoskeleton active remodeling is too complex to be studied in vivo. Simplified in vitro systems provide a controlled environment for studying systematically the role of constituent proteins. Here we report on an in vitro experimental study of the active self-organization of actin by myosin II motor proteins in bulk. The active patterns shown here and their dynamics of formation involve totally different mechanisms compared to passive systems (not including motor proteins). Our findings show a wide range of active processes and dynamics, many of them not predicted by current theoretical models. This system is able to generate active networks, asters and even rings depending on myosin II and bundling proteins concentrations. Unexpectedly, we found that the addition of passive bundling proteins (i.e., fascin) is indispensable for pattern formation. We show that the nature of the reorganization process is complex and can generate metastable patterns at short time scales which can further transform to their final steady state structure as time evolves. The time scales of these transformations can range from minutes to hours depending on the type of the pattern. In addition, we find that the motors generate the formation of the patterns, but above a critical concentration they can also destroy them or even inhibit the polymerization and bundling of actin filaments. Our results therefore demonstrate that one possible way to tune the assembly or disassembly of these structures can be done just by changing the concentration/activity of myosin II motors. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071217/007423e5/attachment.htm From dcohen at bgu.ac.il Thu Dec 20 12:53:23 2007 From: dcohen at bgu.ac.il (Doron Cohen) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Condensed Matter Seminar Message-ID: Condensed Matter Seminar DATE: 31-12-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Time development of bacterial colony growth SPEAKER: Avraham Be`er, The Center for Nonlinear Dynamics University of Texas at Austin, Austin TX USA ABSTRACT/COMMENTS: The failure of current models of bacterial colony growth to incorporate time development data has rendered them inadequate to accurately describe the growth mechanism. Previous studies of bacterial colony growth have been largely qualitative and are limited to pictures obtain?ed at the end of the growth period. Various models have been developed in order to explain the growth of the colonies, but with no experimental data of the time development, the models fail to successfully expose the growth mechanism. In particular, time resolved measurements of the interaction between competitive neighboring colonies have never been performed. Quantification of the competition between colonies is a key method to expose the capability of the bacteria to create long distance signaling. Using a newly developed method, we study experimentally the latent time development of growth patterns formed by Paenibacillus type-T bacteria in poor media. The colonies show branching-like patterns similar to those obtained in viscous fingering, electro deposition and DLA systems. On the macro scale, we perform quantitative experimental investigations and analyze growing complex structures. In particular, we go beyond the studies of individual colonies and explore colony-colony interactions (see image below) in order to elucidate long distance signaling and communication effects. From dcohen at bgu.ac.il Thu Dec 20 11:58:12 2007 From: dcohen at bgu.ac.il (Cohen Doron) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Condensed Matter Seminar Message-ID: <476A3CB4.3040100@bgu.ac.il> Condensed Matter Seminar DATE: 31-12-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Time development of bacterial colony growth SPEAKER: Avraham Be`er, The Center for Nonlinear Dynamics University of Texas at Austin, Austin TX USA ABSTRACT/COMMENTS: The failure of current models of bacterial colony growth to incorporate time development data has rendered them inadequate to accurately describe the growth mechanism. Previous studies of bacterial colony growth have been largely qualitative and are limited to pictures obtain?ed at the end of the growth period. Various models have been developed in order to explain the growth of the colonies, but with no experimental data of the time development, the models fail to successfully expose the growth mechanism. In particular, time resolved measurements of the interaction between competitive neighboring colonies have never been performed. Quantification of the competition between colonies is a key method to expose the capability of the bacteria to create long distance signaling. Using a newly developed method, we study experimentally the latent time development of growth patterns formed by Paenibacillus type-T bacteria in poor media. The colonies show branching-like patterns similar to those obtained in viscous fingering, electro deposition and DLA systems. On the macro scale, we perform quantitative experimental investigations and analyze growing complex structures. In particular, we go beyond the studies of individual colonies and explore colony-colony interactions (see image below) in order to elucidate long distance signaling and communication effects. ? From dcohen at bgu.ac.il Thu Dec 20 11:41:21 2007 From: dcohen at bgu.ac.il (Cohen Doron) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Condensed Matter Seminar Message-ID: <476A38C1.2090006@bgu.ac.il> Condensed Matter Seminar DATE: 31-12-2007 TIME: 11:30am (Mon) PLACE: Physics building (#54) room 207 TITLE: Time development of bacterial colony growth SPEAKER: Avraham Be`er, The Center for Nonlinear Dynamics University of Texas at Austin Austin TX USA ABSTRACT/COMMENTS: The failure of current models of bacterial colony growth to incorporate time development data has rendered them inadequate to accurately describe the growth mechanism. Previous studies of bacterial colony growth have been largely qualitative and are limited to pictures obtain?ed at the end of the growth period. Various models have been developed in order to explain the growth of the colonies, but with no experimental data of the time development, the models fail to successfully expose the growth mechanism. In particular, time resolved measurements of the interaction between competitive neighboring colonies have never been performed. Quantification of the competition between colonies is a key method to expose the capability of the bacteria to create long distance signaling. Using a newly developed method, we study experimentally the latent time development of growth patterns formed by Paenibacillus type-T bacteria in poor media. The colonies show branching-like patterns similar to those obtained in viscous fingering, electro deposition and DLA systems. On the macro scale, we perform quantitative experimental investigations and analyze growing complex structures. In particular, we go beyond the studies of individual colonies and explore colony-colony interactions (see image below) in order to elucidate long distance signaling and communication effects. ? From Ibar at bgu.ac.il Thu Dec 20 17:28:52 2007 From: Ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-27 Lasers Seminar Message-ID: <023001c8431d$070af3d0$ac574884@ilap> ANNOUNCEMENT==> Special Lasers Seminar DATE: 27-12-2007 TIME: 11:00 am (Thu) PLACE: Physics building (#54) room 207 TITLE: Probing Diffusion in Artificial and Bacterial Membranes with Fluorescence Correlation Spectroscopy SPEAKER: Anat Dulman, Department of Physics, Ben Gurion University of the Negev ABSTRACT/COMMENTS: There are indications that DNA- and protein-membrane interactions play a the major role in the cell division process. It was proposed that these interactions cause membrane heterogeneity which serves as one of the markers directing cell division process. The goal of this work was to study the effect of DNA - membrane interactions on the membrane structure in E. Coli by measuring the diffusion kinetics of membranal probes. The combination of Fluorescence Correlation Spectroscopy (FCS) technique with Scanning Confocal Microscopy (SCM) allows us to focus on a precise location at the membrane and measure the kinetics of probe diffusion in a wide range of time scales. Our main observation is that DNA - membrane interactions do affect probe dynamics in the membrane, indicating that the structural state of the membrane depends on DNA attachment to it. The diffusion kinetics slows down upon destroying DNA links to the membrane. Moreover, we find that this slowing down is dependent on the presence of the outer membrane and peptidoglycan layer: disposing off them accelerates probe diffusion. The interpretation of our results within a simple model is proposed. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071220/b8334296/attachment.htm From physics at bgu.ac.il Sun Dec 23 09:44:56 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-26 Astrophysics and Cosmology Seminar Message-ID: <200712230744.JAA37970324@tzin.bgu.ac.il> Astrophysics and Cosmology Seminar DATE: 26-12-2007 TIME: 12:00 noon (Wed) PLACE: Physics building (#54) room 207 TITLE: Gravitational waves from short gamma-ray bursts from primordial and dynamically formed neutron star binaries. SPEAKER: Dafne Guetta, University of Rome ABSTRACT/COMMENTS: The most popular progenitor model of short-hard gamma-ray bursts(SHBs) invokes the merger of two double neutron stars. These can be \"primordial\" or can form dynamically by binary exchange interactions in globular clusters during core-collapse. For primordial binaries, the time delay between formation and merger is expected to be short, $\\tau\\sim0.1$~Gyr, implying that the redshift distribution of merger events should follow that of star-formation (SF). For dynamically formed DNSs, the time delay between star-formation and merger is dominated by the cluster core-collapse time, rather than by the gravitational wave (GW) inspiral time, yielding delays comparable to the Hubble time. In this case the redshift distribution of merger events do not follow the SF but the distribution is shifted to low-z values.SHBs should emit most of their binding energy in gravitational radiation.In this talk I explore the implications of both models for gravitational waves detection by current and next generation gravitational wave detectors.We find that if SHBs are populated by a large number of low luminous bursts (LL GRBS: $L<10^{47}$ erg/s) the chance for detection by LIGO and VIRGO is not negligible for both models.However GW from dynamically formed DNSs have a better chance to be detected.We find that future GW telescopes (LIGO II) will be able to detect several mergers per year for both models. From ibar at bgu.ac.il Tue Dec 25 21:35:28 2007 From: ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2008-01-01 Lasers Seminar Message-ID: ANNOUNCEMENT==> Lasers Seminar DATE: 01-01-2008 TIME: 15:30 am (Tue) PLACE: Physics building (#54) room 207 TITLE: Femtosecond Fiber Lasers and Their Applications SPEAKER: Dr. Jacob (Kobi) Lasri, OptiSiv Ltd., Kibbutz Einat ABSTRACT/COMMENTS: Femtosecond fiber lasers, with their compact size, high efficiency, and maintenance-free operation are challenging the bulk solid-state lasers in many areas of science and technology, including fundamental research, material processing, high-speed optical communication, metrology, and medical imaging. Furthermore, with their ease of manufacture and high-power capabilities, the potential of femtosecond fiber lasers is far from being exhausted. In this talk, the principle operation of ultrafast fiber lasers and chirped-pulse fiber amplifiers will be described. Next, various scientific and commercial applications will be reviewed, with particular focus on femtosecond fiber lasers for phase-stabilized optical frequency comb technology. The talk will conclude with possible future directions. Prof. I. Bar Department of Physics Ben-Gurion University of the Negev Beer Sheva 84105 ISRAEL? -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071225/c6cd1586/attachment.htm From ibar at bgu.ac.il Tue Dec 25 21:37:47 2007 From: ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2008-01-01 Lasers Seminar Message-ID: ANNOUNCEMENT==> Lasers Seminar DATE: 01-01-2008 TIME: 15:30 pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Femtosecond Fiber Lasers and Their Applications SPEAKER: Dr. Jacob (Kobi) Lasri, OptiSiv Ltd., Kibbutz Einat ABSTRACT/COMMENTS: Femtosecond fiber lasers, with their compact size, high efficiency, and maintenance-free operation are challenging the bulk solid-state lasers in many areas of science and technology, including fundamental research, material processing, high-speed optical communication, metrology, and medical imaging. Furthermore, with their ease of manufacture and high-power capabilities, the potential of femtosecond fiber lasers is far from being exhausted. In this talk, the principle operation of ultrafast fiber lasers and chirped-pulse fiber amplifiers will be described. Next, various scientific and commercial applications will be reviewed, with particular focus on femtosecond fiber lasers for phase-stabilized optical frequency comb technology. The talk will conclude with possible future directions. Prof. I. Bar Department of Physics Ben-Gurion University of the Negev Beer Sheva 84105 ISRAEL? -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071225/28b32402/attachment.htm From ibar at bgu.ac.il Tue Dec 25 21:48:00 2007 From: ibar at bgu.ac.il (Ilana Bar) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2008-01-01 Lasers Seminar Message-ID: ANNOUNCEMENT==> Lasers Seminar DATE: 01-01-2008 TIME: 3:30pm (Tue) PLACE: Physics building (#54) room 207 TITLE: Femtosecond Fiber Lasers and Their Applications SPEAKER: Dr. Jacob (Kobi) Lasri, OptiSiv Ltd., Kibbutz Einat ABSTRACT/COMMENTS: Femtosecond fiber lasers, with their compact size, high efficiency, and maintenance-free operation are challenging the bulk solid-state lasers in many areas of science and technology, including fundamental research, material processing, high-speed optical communication, metrology, and medical imaging. Furthermore, with their ease of manufacture and high-power capabilities, the potential of femtosecond fiber lasers is far from being exhausted. In this talk, the principle operation of ultrafast fiber lasers and chirped-pulse fiber amplifiers will be described. Next, various scientific and commercial applications will be reviewed, with particular focus on femtosecond fiber lasers for phase-stabilized optical frequency comb technology. The talk will conclude with possible future directions. Prof. I. Bar Department of Physics Ben-Gurion University of the Negev Beer Sheva 84105 ISRAEL? -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071225/24c0a2fb/attachment.htm From nano at bgu.ac.il Wed Dec 26 09:36:01 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-26 nanotechnology workshop-CHANGE OF ROOM Message-ID: <001901c84791$f6aea5d0$1b0e4884@estinano> Attention: change of room Nanotechnology workshop, Wednesday December 26, 12:00 building 59, room 235,Chemical Engineering seminar room Title : Using Magnetic Anisotropy for Engineering Information Storage Devices Speaker: Dr. Amit Kohn Department of Materials University of Oxford, UK Abstract: Most digital information is stored using magnetic materials, which are the basis for all required components: media, write heads and read sensors. To enable future increase in data storage capacity, perpendicular recording media and spin polarized electrodes for sensors are important developments. In this talk, I present three studies in which we use magnetic anisotropy (variation of magnetic properties as a function of direction in the material) to engineer the properties of such media and electrodes. Additionally, I discuss how this research drives the development of electron microscopy methods needed to image magnetic structures at the nanometer scale. Shape anisotropy is used in electrochemically deposited nano-pillars that are developed for high-density perpendicular recording media. We explain the roles of geometrical configuration, grain size, and impurities on the magnetic properties of these pillars by comparing magnetic imaging, structural data, and micromagnetic computer simulations. Magnetocrystalline anisotropy is utilized in molecular beam epitaxial growth of a model Fe/MgO/Fe tunnel-junction sensor. We describe how Co/Fe bi-layers can serve as the reference memory state due to an epitaxial relation that causes the hexagonal Co layer to exhibit four-fold anisotropy aligned with the cubic Fe layer. Another study relates to sputter-deposited amorphous CoFeB, the electrode material in magnetic tunnel junctions with the highest reported magneto-resistance values. Magnetic anisotropy can be induced in this material despite its amorphous structure. The accepted explanation for this phenomenon is pair-ordering even though experimental evidence is lacking. We measured short-range-order in CoFeB using electron diffraction and then examine the structural reason for induced anisotropy. Our studies emphasize the importance of controlling microstructure and composition when designing the next generation of information storage devices. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071226/a8d0c423/attachment.htm From gideonc at bgu.ac.il Wed Dec 26 21:11:27 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-27 Colloquium - Cancellation Message-ID: <200712261911.VAA43233226@tzin.bgu.ac.il> Colloquium - Cancellation DATE: 27-12-2007 TIME: PLACE: TITLE: Because of the protest (closed gates) there will be no colloquium this Thursday. SPEAKER: , ABSTRACT/COMMENTS: From idobd at bgu.ac.il Thu Dec 27 12:16:54 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Particles and Fields Seminar Message-ID: <200712271016.MAA44228260@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 31-12-2007 TIME: 1:00 pm (Mon) - Notice the different time! PLACE: Physics building (#54) room 207 TITLE: Novel symmetries from heterotic string models SPEAKER: Alon Faraggi, Liverpool University ABSTRACT/COMMENTS: I will discuss two novel symmetries unravelled in recent studies of phenomenological free fermion string models. The first is the evidence for the existence of spinor-vector duality in heterotic string models. The second is a novel low scale U(1) symmetry associated with the suppression of proton decay mediating processes. The U(1) symmetry arises in a class of three generation free fermion models and suppresses proton decay from dimension four, five and six operators. While forbidding baryon number violation, and hence suppressing proton decay, it allows lepton number violation, and hence allowing R-parity violation. From gideonc at bgu.ac.il Thu Dec 27 18:42:24 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Colloquium - Note the change of day Message-ID: <200712271642.SAA44565118@tzin.bgu.ac.il> Colloquium - Note the change of day DATE: 31-12-2007 TIME: 3:30pm (Mon) PLACE: Physics building (#54) room 207 TITLE: Memory and relaxation in nanomagnets SPEAKER: Prof. Sushanta Dattagupta , Director, Indian Institute of Science Education and Research, Kolkata, India. ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collq0708_A/Sushanta.html Refreshments are served at 3:20pm From physics at bgu.ac.il Sun Dec 30 08:44:36 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Physics Colloquium Message-ID: <200712300644.IAA48309024@tzin.bgu.ac.il> Physics Colloquium DATE: 31-12-2007 TIME: 3:30pm (Mon) PLACE: Physics building (#54) room 207 TITLE: Memory and relaxation in nanomagnets SPEAKER: Prof. Sushanta Dattagupta , Director, Indian Institute of Science Education and Research, Kolkata, India. ABSTRACT/COMMENTS: A collection of single domain nanomagnetic particles is an epitome of Brownian motion, time-window effects, hysteresis and \"glassy\" physics especially if there is a distribution of particle-sizes and hence a distribution of relaxation times. I will illustrate some of these ideas in terms of experiments in a Stern-Gerlach setup, on Moessbauer spectroscopy and on magnetization measurements. The effect of interaction, especially of dipolar nature, will be shown to have important influence on relaxation and concomitant memory behaviour. Turning away from classical to quantum nanomagnets I will show how classical to quantal transitions can be seen in molecular magnets either by increasing the size of the spin or the dissipative coupling with the environment. From physics at bgu.ac.il Sun Dec 30 09:08:18 2007 From: physics at bgu.ac.il (physics@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2008-01-03 Physics Colloquium Message-ID: <200712300708.JAA48484226@tzin.bgu.ac.il> Physics Colloquium DATE: 03-01-2008 TIME: 3:30pm (Thu) PLACE: Physics building (#54) room 207 TITLE: Stochastic simulations of genetic regulatory networks in cells SPEAKER: Prof. Ofer Biham, Dept of Physics, Hebrew University Jerusalem ABSTRACT/COMMENTS: Extensive effort in the field of systems biology in recent years has focused on the analysis of cellular networks. These networks consist of interacting genes, which regulate each other\'s expression. Recent studies have shown that these networks are typically sparse and include recurring modules or motifs. To analyze the function of genetic networks, one needs to simulate their dynamics. Since the networks often exhibit strong fluctuations, stochastic methods, based on the master equation, are required. In this talk I will consider a class of genetic modules such as the toggle switch [1,2], the mixed feedback loop and the repressilator. Some of these modules include only transcriptional regulation, while others also include post-transcriptional regulation by small non-coding RNAs [3] and post-translational regulation by protein-protein interactions. I will show that in modules which include feedback, fluctuations give rise to crucial quantitative and qualitative effects. More complete understanding of the function of genetic networks will require to simulate large complex networks, which consist of many interacting modules. While direct integration of the master equation is suitable for the analysis of small modules, it becomes infeasible in the case of complex networks, because the number of equations increases exponentially with the number of genes in the network. As a potential solution to this problem, I will present the multi-plane method [4]. This method has been used for chemical networks, where it provides a dramatic reduction in the number of equations and enables to perform stochastic simulations of complex reaction networks. Current efforts are aimed at extending the method to the more general reaction processes and interactions which appear in genetic networks. [1] A. Lipshtat, A. Loinger, N.Q. Balaban and O. Biham, Genetic toggle switch without cooperative binding, Phys. Rev. Lett. 96, 188101 (2006). [2] A. Loinger, A. Lipshtat, N.Q. Balaban and O. Biham, Stochastic simulations of genetic switch systems, Phys. Rev. E 75, 021904 (2007). [3] Y. Shimoni, G. Friedlander, G. Hetzroni, G. Niv, S. Altuvia, O. Biham and H. Margalit, Regulation of gene expression by small non-coding RNAs: a quantitative view, Molecular Systems Biology 3, 138 (2007). [4] A. Lipshtat, O. Biham, Efficient simulations of gas-grain chemistry in interstellar clouds, Phys. Rev. Lett. 93, 170601 (2004). From idobd at bgu.ac.il Sun Dec 30 11:06:54 2007 From: idobd at bgu.ac.il (idobd@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Particles and Fields Seminar Message-ID: <200712300906.LAA48682817@tzin.bgu.ac.il> Particles and Fields Seminar DATE: 31-12-2007 TIME: 10:00am (Mon) PLACE: Physics building (#54) room 207 TITLE: Z\'-mediated Supersymmetry Breaking SPEAKER: Gil Paz, IAS ABSTRACT/COMMENTS: In this talk I will describe a new mechanism for mediation of supersymmerty breaking via a U(1)\' gauge interaction, were the U(1)\' also plays a crucial role in solving the mu problem. Such constructions can be realized fairly naturally and are quite frequent in top-down constructions. The low energy spectrum generically contains heavy sfermions, Higgsinos, exotics, and Z\' (~ 10-100 TeV); light gauginos ~ 100-1000 GeV, of which the lightest can be wino-like; and a light Higgs in the range 140-180 GeV. Typically, the singlino is also light and may give interesting signals at the LHC. Such models can be viewed as a specific realization of a modest version of split supersymmetry. From nano at bgu.ac.il Mon Dec 31 12:51:09 2007 From: nano at bgu.ac.il (Nano) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2008-01-02 nanotechnology workshop Message-ID: <006801c84b9b$0de93320$1b0e4884@estinano> Nanotechnology workshop, Wednesday January 2, 12:00 building 29, room 306,Chemistry Department seminar room Title : Mechanical Model for Self-Polarization of Cells Speaker: Assaf Zemel Department of Materials and Interfaces Weizmann Institute -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.bgu.ac.il/pipermail/phys-seminars/attachments/20071231/720d0115/attachment.htm From gideonc at bgu.ac.il Mon Dec 31 12:56:48 2007 From: gideonc at bgu.ac.il (gideonc@bgu.ac.il) Date: Tue Feb 17 13:18:28 2009 Subject: [Phys-seminars] 2007-12-31 Colloquium - Reminder Message-ID: <200712311056.MAA50446413@tzin.bgu.ac.il> Colloquium - Reminder DATE: 31-12-2007 TIME: 3:30pm (Mon) PLACE: Physics building (#54) room 207 TITLE: Memory and relaxation in nanomagnets SPEAKER: Prof. Sushanta Dattagupta , Director, Indian Institute of Science Education and Research, Kolkata, India. ABSTRACT/COMMENTS: For abstract please enter the link below: http://physweb.bgu.ac.il/EVENTS/COLLOQ/collq0708_A/Sushanta.html Refreshments are served at 3:20pm