3 MAR 2021
15:30 - 17:30

Starting from a model of ZFC+GCH, iterated forcing is a method of building a new larger model in which (for example) the continuum hypothesis fails and in fact the continuum $c$ (the cardinality of the set R of real numbers) can become arbitrarily large. Several other so called "cardinal characteristics" may be changed as well: for example, the number cov(null) (the smallest size of a family of Lebesgue null sets whose union is all of R) or the similarly defined number cov(meager), where null sets are replaced by meager sets (or equivalently: by closed nowhere dense sets. For example, iterating Cohen's original forcing one can get a model where cov(null) is still small (aleph1), while cov(meager) becomes c (which will be large).
In my talk I will present a method for iterating forcing notions that allows us to selectively increase certain cardinals to prescribed values. In particular, intersecting a forcing notion with elementary submodels of the universe will yield new forcing notions. If the submodels are carefully chosen, then an analysis of the properties of these new forcing notions will allows us to compute the value of certain cardinal characteristics in the generic extension.
To join this webinar, please send an email to r.zoghi@gmail.com.

3 MAR 2021
17:00 - 18:00

Abstract: The discovery of the Standard Model Higgs boson in 2012 represented a thrilling triumph for the particle physics community and an outstanding achievement for the LHC. Even though the unraveling of the puzzle of the Higgs boson completed the final chapter of the Standard Model's book, a number of major questions in particle physics remain unresolved. In my presentation, I will discuss how the SM Higgs boson can be exploited for new discoveries. In particular, I will review a set of searches where the Higgs boson decays in an exotic, non-SM, fashion. I will conclude my presentation with an overview of the future of the LHC.


Indico: https://indico.particles.ipm.ir/indico/event/405

3 MAR 2021
13:30 - 15:00

The properties of galaxies are known to be largely influenced by their local and global environment. One of the important and unresolved aspects of structure formation is the prediction of the structural and dynamical properties of a virialized object, due to a large reflection of the nonlinear dynamics involved. In reality, galaxies plunge into galaxy groups and clusters, and their properties are affected by their environments. In this talk, I am going to show the role of group dynamics on the evolution of galaxies using observational surveys, semi-analytic model, and hydrodynamical simulations for galaxy formation to improve the galaxy-halo connection scenario. Furthermore, I will present the first result of tracking the evolution of galaxies with considering the different distance to the filament in which help us to understand how galaxy morphology, ages, gas fractions, and star formation rates are observed to steadily transform with environmental density across the cosmic web.

2 MAR 2021
14:00 - 15:00

Abstract:

In the 1980s, Armin Uhlmann described a natural generalisation of Berry phase to mixed states which has come to be known as Uhlmann phase. I will describe a series of recent results characterising the Uhlmann phase of subsystems in quantum gravity. First, assuming replica wormholes contribute to the path integral, I will show that measurements of the Uhlmann phase of Hawking radiation allows one to reconstruct the phase space of the interior of a black hole (past the Page time), providing a protocol for the recovery of all infalling classical information. This is a generalisation of a previous result concerning entanglement wedges in holography. Next, I describe a path integral formula for the Uhlmann phase of a generic highly entangled system, explaining how it appears to inevitably involve an extra dimension generated by modular flow, despite a lack of any holographic assumptions. Finally, I comment on the operational meaning of Uhlmann phase, and how it's significance may relate to decoherence.


Date: Tuesday, March 2th

2 p.m. - 3 p.m. (Tehran time)


Zoom. (click)

Meeting ID: 812 4428 3537

Passcode: 047580

2 MAR 2021
14:00 - 15:00

Abstract:

In the past decade there has seen an explosion of interest in two dimensional monolayers which started from an atom-thick plane of carbon known as graphene. The low dimensional material opens a new window over the many technological applications and new emerging science. Different two dimensional monolayers had been discovered with a wide range of Physical properties such as metals, semiconductors, insulators, superconductors and ferroelectrics. For a "long time", the magnetic order was absent in the large variety of two-dimensional (2D) systems. A few years ago, a new type of 2D materials with long-range magnetic order was discovered. Ferromagnetism below ~50 K was experimentally observed in chromium trihalides exfoliated down to 1-nm thickness. Very recently, room-temperature ferromagnetism was experimentally reported in Transition Metal Dichalcogenide (TMD) monolayers. However, still there are many unanswered questions about the origin and engineering of low dimensional magnetism for future applications. In this talk I have a brief review on recent theoretical and experimental understanding in the field of 2D magnetism and give a report to our un/published works.


Date: Wednesday, March 3, 2021

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

1 MAR 2021
16:00 - 18:00

Grammar in Optimality Theory


https://www.skyroom.online/ch/ipmseminars/ipm-seminars-2021

User: biweeklyseminars
Pass: biweeklyseminars

1 MAR 2021
11:00 - 12:00

Based on
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.044801


Abstract: In Tanaka s paper, a new mechanism for generation of attosecond pulses in X-ray free electron lasers (XFELs) has been proposed. Ultrashort pulses offer a high temporal resolution, and the opportunity to probe and control ultrafast processes in matter. During the six decades of lasers there have been some significant revolutions in their pulse duration. With each instance toward shorter pulses new scientific realms emerged. Mode-locking followed by high harmonic generation made femto- and atto- physics possible. They suffer significant limitations to achieve shorter and more intense pulses. X-ray free-electron lasers are a promising new direction towards atto- and zepto- physics with intense pulses. The state-of-the-art XFELs are in femto range, but, recently there have been some proposals for XFEL to achieve shorter pulses. Amongst them, Tanaka s paper is a fascinating idea with a potential for future experiments in XFELs. I will discuss the paper with some introductory remarks on FEL physics and ultrashort pulses in this Journal Club session.


https://meet.google.com/cph-xgtg-wfw

27 FEB 2021
13:00 - 17:00

Workshop (online)
Feb 27, 2021 from 13 to 17

24 FEB 2021
19:30 - 20:30

A variety $V$ of codimension $r$ in a projective space $mathbb{P}^n$ is called a set-theoretic complete intersection if $V$, as a set, is the intersection of exactly $r$ hypersurfaces in $mathbb{P}^n$. I will discuss the history of the general problem, which varieties $V$ are s.t.c.i., with special attention to the still open problem, is every irreducible nonsingular curve in $mathbb{P}^3$ a set-theoretic complete intersection? In particular I will mention several algebraic criteria, including local cohomology that can in principle be used to show that certain varieties are not s.t.c.i.
To get more information about the colloquium, join to the following google group:
https://groups.google.com/g/ipm-math-colloquium

24 FEB 2021
11:00 - 12:00

Abstract: In this talk we use holography to discuss entanglement entropy and mutual information in a strongly coupled field theory with a critical point and see whether we can obtain the critical exponents using mutual information. This talk is based on e-Print: 2002.09993 [hep-th].


Indico: https://indico.particles.ipm.ir/indico/event/404

24 FEB 2021
18:00 - 19:30

A regular rotating MOG (modified gravity) compact object is derived that reduces to the Kerr black hole when the parameter α = 0. Physical consequences of the dark compact object, which is regular everywhere in spacetime for α > α_crit = 0.674 and is a rotating Kerr-MOG black hole for α < α_crit are investigated.steps.