25 NOV 2020
15:30 - 17:30

Some important C*-algebras have been recently flagged and studied as Fraisse limits. In the first part of my talk, I will review the Fraisse theory of C*-algebras (or more generally, of metric structures)--in the context of category theory (as opposed to model theory)--and give examples of approximately finite-dimensional non-commutative C*-algebras which appear as Fraisse limits and exabit Cantor-space-like universality/homogeneity properties. In the second part of my talk, I will show how one can apply the fact that a C*-algebra A is the Fraisse limit of a category of C*-algebras, which is sufficiently closed under taking tensor products of its objects and morphisms, to show that A is "self-absorbing" in a very "strong" sense (a C*-algebra is self-absorbing if it is isomorphic to its tensor product with itself). I will use this result to sketch a new and much easier proof for the notorious fact that the "Jiang-Su algebra" is strongly self-absorbing.
To join this webinar, please send an email to r.zoghi@gmail.com.

25 NOV 2020
11:00 - 12:00

Abstract: In my first talk, I review some basic concepts such as the early thermalization puzzle, hydrodynamization paradigm, and stability/casualty problem. I also speculate on a possible way to understand hydrodynamization in conformal theories. In my second talk, I present our results on the hydrodynamization in the first-order causal and stable(FOCS) hydrodynamics, with an emphasis on the differences between the FOCS and more traditional approaches.


https://journals.aps.org/prd/abstract/10.1103/PhysRevD.102.036022


https://www.skyroom.online/ch/ipm-particles/school-of-particles-and-accelerators-weekly-meeting


Indico: https://indico.particles.ipm.ir/indico/event/390

25 NOV 2020
13:30 - 15:00

We revisit the question of what mechanism is responsible for the spins of halos of dark matter. The answer to this question is of high importance for modeling galaxy intrinsic alignment, which can potentially contaminate current and future lensing data. In particular, we show that when the dark matter halos pass nearly by each other in dense environments-- namely halo assemblies-- they swing and spin each other via exerting mutual tidal torques. We show that this has a significant contribution to the spin of dark matter halos comparable to that of calculated by the so-called tidal torque theory (TTT). We use the results of state-of-the-art simulation of Illutris to check the prediction of this theory against the simulation data.
To join the seminar, please click on the following link

https://www.skyroom.online/ch/soa/weekly-seminar

Then click on the guest bottom to participate

25 NOV 2020
14:00 - 15:00

Abstract:

Thanks to magnetocrystalline anisotropy in van der Waals magnetic materials, the Mermin-Wagner restriction is deviated and two-dimensional (2D) magnetic materials had been discovered recently. The combination of magnetic and unique properties of 2D materials has been rapidly attracted the attention of researchers to novel magnetic 2D materials. So, the control of spin-spin interactions in magnetic systems is an essential topic related to the fundamental physics of quantum magnetism as well as applied spintronics-based technology. In this talk, the magnetic properties of monolayer CrI3, as a representative of 2D magnetic materials, are discussed. Density functional theory (DFT)-based calculations are used to extract a suitable spin model Hamiltonian that reproduces accurate and viable magnetic properties of monolayer CrI3. We present the mechanical strain and electric field dependence of various spin-spin interactions, consisting of symmetric isotropic exchange, magnetic anisotropy, and Dzyaloshinskii-Moriya (DM) interactions in the monolayer.


Date: Wednesday, November 25, 2020
Time: 14:00-15:00

To join the webinar, please follow this link:
https://www.skyroom.online/ch/schoolofphysics/condensed-matter-and-statistical-physics
and log in as guest.

Organized by: Condensed Matter and Statistical Physics Group, School of Physics (IPM)

Queries about this event should be addressed to Dr. A. Faridi at azadeh.faridi@ipm.ir

25 NOV 2020
19:30 - 21:30

Abstract: The discovery of the quark-gluon plasma that forms in heavy-ion collision experiments provides a unique opportunity to study the properties of matter under extreme conditions, as the quark-gluon plasma is the hottest, smallest, and densest fluid known to humanity. Studying the quark-gluon plasma also provides a window into the earliest moments of the universe, since microseconds after the Big Bang the universe was filled with matter in the form of the quark-gluon plasma. For more than two decades, the community has intensively studied the quark-gluon plasma with the help of a rich interaction between experiment, theory, phenomenology, and numerical simulations. From these investigations, a coherent picture has emerged, indicating that the quark-gluon plasma behaves essentially like a relativistic liquid with viscosity. More recently, state-of-the-art numerical relativity simulations strongly suggested that viscous and dissipative effects can also have non-negligible effects on gravitational waves produced by binary neutron star mergers. But despite the importance of viscous effects for the study of such systems, a robust and comprehensive theory of general relativistic fluids with viscosity is still lacking. This is due, in part, to difficulties to preserve causality upon the inclusion of viscous and dissipative effects into theories of relativistic fluids. In this talk, we will survey the history of the problem and report on a new approach to relativistic viscous fluids that paves the way for the systematic investigation of dissipative phenomena in general relativity.


https://us02web.zoom.us/meeting/register/tZ0pc--vrzwsHdz88USL3bZI6npJUwq166dH