Seminars

• Astrophysics and Cosmology Seminar

  Detecting individual stars at cosmological distances with gravitational lensing

  Ashish Meena, BGU

  02 Apr 2025, 11:10 Sacta-Rashi Building for Physics (54), room 207

• Quantum optics seminar

  Atomic arrays as programmable quantum processors and sensors

  Ran Finkelstein, Tel Aviv University

  02 Apr 2025, 16:00 Zoom Only

Astrophysics and Cosmology

The largest objects: galaxy clusters

Uri Keshet

Galaxy clusters, as the largest virialized objects ever to form in the Universe, link cosmology and astrophysics. These 'island-universe' objects are mainly composed of dark matter and a hot, dilute plasma. Their stability is an open question, as the strong X-ray emission should have naively led to catastrophic cooling and collapse. Over the past decade, mysterious spiral structures were found in practically all clusters. They may be driven by the giant black hole lurking in the center of every cluster, for example through the relativistically hot bubbles it injects into the plasma (figure).

High-Energy Physics

Effective Theories and Quantum Gravity

Eran Palti

Effective theories are simplified physics models which neglect high-energy processes. If those theories include gravitational physics, then the omitted high-energy physics must include that of Quantum Gravity. Not all effective theories can be consistently completed at high energies into Quantum Gravity. Those which can are said to belong to the Landscape of effective theories. While those which cannot are said to belong to the Swampland of inconsistent theories. We study what are the criteria which differentiate an effective theory in the Landscape from one in the Swampland.

Seminars

• Astrophysics and Cosmology Seminar

  Detecting individual stars at cosmological distances with gravitational lensing

  Ashish Meena, BGU

  02 Apr 2025, 11:10 Sacta-Rashi Building for Physics (54), room 207

• Quantum optics seminar

  Atomic arrays as programmable quantum processors and sensors

  Ran Finkelstein, Tel Aviv University

  02 Apr 2025, 16:00 Zoom Only

Condensed Matter Theory

Mesoscopics

Ora Entin-Wohlman

*** Molecular junctions and thermoelectricity: studying transport of electrons and of heat through single-molecule bridges (e.g. nano-tubes). Finding bounds on the thermoelectric efficiencies. *** Superconducting-insulator transition: studying the way the conductance of hybrid systems are modified as part of the sample goes superconducting. *** Persistent current in metalic rings: Superconducting fluctuations generate persistent currents around rings even above the superconduction temperature, which may be reduced by proximity to normal metals.

Condensed Matter Experimental

Noise in strongly correlated systems

Grzegorz Jung

Normalized spectral density and R(T) for distinct resistivity states

To many physicist the subject of fluctuations appears esoteric and even pointless; spontaneous fluctuations seem nothing but an unwanted evil which only an unwise experimenter would encounter. In reality, noise enables a deep insight into physics of the system. Recently, we have employed noise to discriminate various resistivity states in the ferromagnetic insulating manganite La0.86Ca0.14MnO3. Different states arise due to transitions between local minima of the electronic glass potential landscape. Remarkably, freezing into the glass state is marked by the onset of non-Gaussian noise.

Seminars

• Astrophysics and Cosmology Seminar

  Detecting individual stars at cosmological distances with gravitational lensing

  Ashish Meena, BGU

  02 Apr 2025, 11:10 Sacta-Rashi Building for Physics (54), room 207

• Quantum optics seminar

  Atomic arrays as programmable quantum processors and sensors

  Ran Finkelstein, Tel Aviv University

  02 Apr 2025, 16:00 Zoom Only

Biological and Soft Matter Physics

Single Cell Dynamics

Mario Feingold

During the lifetime of a bacterium it elongates linearly in three distinct regimes.

We use single cell phase-contrast and fluorescence time-lapse microscopy to monitor 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.

Atomic, Molecular and Optical Physics

Attosecond science and nanophotonics Lab

Eugene Frumker

*Tracing and control of electronic motion in atoms, molecules, and nanostructures in space and time (4D). Progress in lightwave electronics. *Table-top XUV and soft X-ray laser-like sources. Nano-scale spatial resolution to optical science of attosecond pulses. *New dynamic imaging modalities – significantly improved spatial/temporal resolution, new contrast imaging for lifescience and nanotechnology. *And much more…