Events
Astrophysics and Cosmology Seminar
Tracing the virial shocks of galaxy clusters
Mr. Gideon Ilani
Bgu
Wed, 20 Oct 2021, 11:10
Sacta-Rashi Building for Physics (54), room 207
Abstract: Galaxy clusters are massive virialized objects, found at the nodes of the cosmic web. These dark-matter potential wells, filled with hot intracluster medium (ICM) plasma, accrete cold gas and galaxies from their surroundings. Clusters were long suspected to be surrounded by strong virial shocks, which heat the gas, accelerate particles, and amplify magnetic fields, although their detection was only established in recent years. I will review the detection of virial shocks around single and stacked clusters, using different wavelengths, and present new methods to trace these shocks.
Quantum optics seminar
Characterization of Co2+ doped matrices for laser applications
Mr. Avry Shirakov
Ben-Gurion University Of The Negev
Wed, 20 Oct 2021, 17:00
ZOOM only
Abstract: Student Seminar!
Note that the seminar is typically at 15:00 but this week it is at 17:00.
The seminar is by ZOOM only! via this link:
https://us02web.zoom.us/j/83334422573?pwd=RTRrQ3I2UmdIOFcxc3VBbmtmNnRYdz09
Abstract:
We investigated three main subjects all of which are concerned with the characterization of Co2+ doped matrices for laser applications. The first subject is the energy level transitions and their decay lifetimes. We have introduced a corrected energy level assignment for Co2+:ZnSe (Co2+:ZnS has the same energy level structure). This new assignment improved the understanding of the energy level transitions and allowed us to measure the kinetics of these transitions. The second subject is the radiative and non-radiative transition lifetimes. Understanding the nature of energy levels transitions is critical in case of new lasing materials. Additionally to Co2+ doped materials, we investigated a more known lasing material, Ti3+ doped Sapphire. The third subject we investigated, is the use of Co2+ doped matrices as a saturable absorber, and the implementation of Co2+ doped matrices into a laser resonator to operate as a passive Q-switch.
Condensed Matter Seminar
"Cornering" the electron in a topological insulator via periodic driving
Dr. Ranjani Seshadri
Bgu
Mon, 25 Oct 2021, 11:30
Sacta-Rashi Building for Physics (54), room 207
Abstract: In this talk, I will be discussing a relatively new entrant to the field of topology
in condensed matter physics called higher-order topological insulators (HOTIs).
Usually, TIs in two dimensions are known to host robust one-dimensional edge
modes. These are related to the bulk properties via a topological invariant such
as the Chern number. However, in HOTIs, there are zero-dimensional corner
modes. These are confined to the vertices of a sample. In this work, a variant
of the well-known Bernevig-Hughes-Zhang model of a two-dimensional TI is
used to construct a two-dimensional HOTI. This equilibrium model has both
topological and non-topological phases. By applying a periodic external perturbation,
one can manipulate these topological phases and change the properties of said
corner modes. We try to understand the bulk-boundary correspondence associated
with such corner states.
Reference: R. Seshadri, A. Dutta, and D. Sen, Phys. Rev. B 100, 115403
Physics Colloquium
TBA
Ernst Rasel
Leibniz University Hannover
Mon, 25 Oct 2021, 16:10
Zoom
Abstract:
Biological and soft-matter physics
Nonlinear Initiation of Side-Branching by Activator-Inhibitor-Substrate Morphogenesis
Prof. Arik Yochelis
Ben-Gurion University Of The Negev
Thu, 28 Oct 2021, 12:10
Sacta-Rashi Building for Physics (54), room 207
Abstract: An understanding of the underlying mechanism of side-branching is paramount in controlling and/or therapeutically treating mammalian organs, such as lungs, kidneys, and glands. Motivated by an activator-inhibitor-substrate approach that is conjectured to dominate the initiation of side-branching in a pulmonary vascular pattern, I demonstrate a distinct transverse front instability in which new fingers grow out of an oscillatory breakup dynamics at the front line without any typical length scale. These two features are attributed to unstable peak solutions in 1D that subcritically emanate from Turing bifurcation and that exhibit repulsive interactions. As such, the generation of finite-amplitude transversely localized oscillations at the front line represents a template from which localized physical structures develop in the transverse direction in 2D. The results are based on a bifurcation analysis and numerical simulations and provide a potential strategy for developing a framework of side-branching for other biological systems, such as plant roots and cellular protrusion.
Condensed Matter Seminar
TBA
Prof. Alexander Shnirman
Kit Karlsruhe, Germany
Mon, 01 Nov 2021, 11:30
Sacta-Rashi Building for Physics (54), room 207
Abstract:
Physics Colloquium
The NEXT big thing in neutrinoless double beta decay
Lior Arazi
Ben-Gurion University
Mon, 01 Nov 2021, 16:10
Ilse Katz Institute for Nanoscale Science & Technology (51), room 015
Abstract: The search for neutrinoless double beta (ββ0ν) decay is one of the central efforts in particle physics today. A detection of this ultra-rare phenomenon will prove that the neutrino is its own antiparticle and demonstrate, for the first time, the non-conservation of the total lepton number. It will further provide a clue for the origin and smallness of the neutrino mass, as well as for the dominance of matter over antimatter in the Universe. Four collaborations in Europe and the US are preparing to search for ββ0ν decay with tonne-scale detectors in the next decade: LEGEND, nEXO, CUPID and NEXT, with an overall budget of about USD 1B. In this talk I will give an overview of the field, with a focus on the NEXT program, of which BGU is a leading member, which searches for ββ0ν decay in Xe-136. I will highlight the unique properties of the experiment, in particular the ability to record, in fine detail, 3D images of events occurring inside the detector, and the potential to identify, in real time, the appearance of a single Ba-136 ion – daughter of Xe-136 – in a detector full of 10^28 xenon atoms.
All events
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