23 SEP 2020
11:00 - 12:00

Abstract: Astrophysical searches of Warm Dark Matter (WDM) candidate in new physics are essential part of the experimental efforts to explore the nature of WDM. In this talk, I will propose an indirect method to search for WDM particles via studying their effects on the polarization of cosmic photons through cosmic photon-sterile neutrino scattering. I will consider GRB photons, galactic and extra galactic radio photons and the CMB photons as sources of cosmic rays and I will report the amount of possible circular polarization for each case via their scattering from the Sterile neutrino. This method might open a new observational window to explore the nature of DM.


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


Indico: https://indico.particles.ipm.ir/indico/event/380

23 SEP 2020
15:30 - 17:00

What factors drive the growth and decay of a pandemic? Can a study of community differences (in demographics, settlement, mobility, weather, and epidemic history) allow these factors to be identified? Has “herd immunity” to COVID-19 been reached anywhere? What are the best steps to manage/avoid future outbreaks in each community? We analyzed the entire set of local COVID-19 epidemics in the United States; a broad selection of demographic, population density, climate factors, and local mobility data, in order to address these questions. What we found will surprise you! (based on arXiv:2007.00159)

23 SEP 2020
14:00 - 15:00

Photothermal Therapy using Graphene Coated Plasmonic Nanoparticles for Cancer treatment

Abstract:

Photothermal therapy (PTT) using plasmonic nanoparticles is one of the effective methods for cancer treatment. In PTT, the amount of temperature rise and the duration of therapy are two important factors which they greatly depend on the selection of appropriate nanoparticles. In this seminar, the optical and photothermal properties of graphene coated nanoparticles including gold, hollow gold-silver core using Mie, Gans and effective medium theories are investigated. Also, the temperature distribution of tumor tissue is calculated by bioheat transfer equations for various sizes and shapes. We show that the surface plasmon resonance (SPR) peak of graphene coated nanoparticles can be easily adjusted inside biological windows by increasing the graphene shell thickness and/or by changing their aspect ratio for spheroidal nanoparticles. Finally, we describe the extent of thermal damage in tumor tissue by using the Arrhenius equation. Our findings introduce a new class of nanoagents which can be used in PTT applications.

23 SEP 2020
15:30 - 17:30

In 2013, Ben Yaacov showed that Shelah's result on definability of local types for stable formulas can be seen as a corollary of Grothendieck's "double-limit" theorem, which characterizes relatively weakly compact sets in certain Banach spaces. Moreover, this theorem applies equally well to continuous logic, and is also valid for formulas that are only stable with respect to a fixed model. In this talk, we examine how this connection applies to stable group theory. We develop the foundations of stable group theory directly from topological dynamics and, in particular, results of Ellis and Nerurkar on weakly almost periodic flows (which are based on the same work of Grothendieck). Moreover, we extend the main ingredients of stable group theory to invariant formulas that are only stable "in a model" and, more generally, to the purely combinatorial setting of an arbitrary group G and an arbitrary left-invariant Boolean algebra of subsets that are "stable in G". Finally, we discuss some applications to additive combinatorics and combinatorial number theory.
Please send an email to r.zoghi@gmail.com to join this lecture.

23 SEP 2020
16:00 - 17:30

Organized by: School of Cognitive Sciences
to receive the link to join online, please send email to theoretical.neurosci.ipm@gmail.com





>> schedule


>> Poster of this session

23 SEP 2020
14:00 - 15:00

http://math.ipm.ac.ir/news/Combin-Webinar-Fall99.pdf

22 SEP 2020
17:30 - 18:30

The counting problem for closed geodesics over negatively curved manifolds, and more generally, for closed orbits of Anosov flows is studied extensively in the literature. However, when the metric is not negatively curved, or when the flow of a vector field is not Anosov, closed geodesics/orbits are not isolated and there are some obstacles for defining a well-behaved count function. We discuss some of these obstructions. In particular, we introduce a function which assigns an integer weight to every compact and open subset of the space of closed geodesics for arbitrary Riemannian metrics over closed manifolds.

To get the access link, register at
https://forms.gle/3AbXZeCucKWCuumR7
by the day before the event.


[ICMC-IMPA-IPM Joint Mathematics Seminars]

22 SEP 2020
14:00 - 15:00

Abstract:

For a given pure state, the entanglement entropy (EE) is a unique measure that characterizes quantum entanglement between two subsystems. However, for mixed states, different quantities which measure quantum or classical correlations between two subsystems have been known, e.g., entanglement of purification and logarithmic negativity. In this talk, first I will review the recent holographic proposals for computing the entanglement wedge cross-section (EWCS) which is dual to entanglement measures for mixed states. Then I will discuss some aspects of EWCS both in static and time-dependent geometries.


Date: Tuesday, 22 September

2 p.m. - 3 p.m.
Skyroom Link: https://www.skyroom.online/ch/schoolofphysics/hepco-group

Skype link for emergency

SkypeLink: https://join.skype.com/cm7iyEUWJVCf

21 SEP 2020
11:00 - 12:00

Based on 2006.04795 [hep-ph].


Abstract: We assess the status of past and future experiments on lepton flavor violating (LFV) muon and tau decays into a light, invisible, axion-like particle (ALP), a. We propose a new experimental setup for MEG II, the MEGII-fwd, with a forward calorimeter placed downstream from the muon stopping target. Searching for µ → eta decays MEGII-fwd is maximally sensitive to LFV ALPs, if these have nonzero couplings to right-handed leptons. The experimental set-up suppresses the (left-handed) Standard Model background in the forward direction by controlling the polarization purity of the muon beam. The reach of MEGII-fwd is compared with the present constraints, the reach of Mu3e and the Belle-II reach from τ → `a decays. We show that a dedicated experimental campaign for LFV muon decays into ALPs at MEG II and Mu3e will be able to probe the ALP parameter space in an unexplored region well beyond the existing astrophysical constraints. We study the implications of these searches for representative LFV ALP models, where the presence of a light ALP is motivated by neutrino masses, the strong CP problem and/or the SM flavor puzzle. To this extent we discuss the majoron in low-scale seesaw setups and introduce the LFV QCD axion, the LFV axiflavon and the leptonic familon, paying particular attention to the cases where the LFV ALPs constitute cold dark matter.


https://www.skyroom.online/ch/ipm-particles/journal-club-ep

20 SEP 2020
08:00 - 11:30

Online :

>> login via guest icon

16 SEP 2020
11:00 - 12:00

Abstract: Our main aim in this paper is to constrain the effective field theory describing the top quark couplings through the e−e+→tt~+jet process. The analysis is carried out considering two different center-of-mass energies of 500 and 3000 GeV including a realistic simulation of the detector response and the main sources of background processes. The expected limits at 95% CL are derived on the new physics couplings such as tt~gamma, tt~Z, and tt~g for each benchmark scenario using the dileptonic tt~ final state. We show that the 95% CL limits on dimensionless Wilson coefficients considered in this analysis could be probed down to 10−4.




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


Indico: https://indico.particles.ipm.ir/indico/event/379

16 SEP 2020
15:30 - 17:30

We show that (assuming large cardinals) set theory is a tractable (and we dare to say tame) first order theory when formalized in a first order signature with natural predicate symbols for the basic definable concepts of second and third order arithmetic, and appealing to the model-theoretic notions of model completeness and model companionship. Specifically we develop a general framework linking generic absoluteness results to model companionship and show that (with the required care in details) a $Pi_2$-property formalized in an appropriate language for second or third order number theory is forcible from some T extending ZFC + large cardinals if and only if it is consistent with the universal fragment of T if and only if it is realized in the model companion of T.
Part (but not all) of our results are conditional to the proof of Schindler and Aspero that Woodin's axiom* can be forced by a stationary set preserving forcing.
Please send an email to r.zoghi@gmail.com to join this lecture.

16 SEP 2020
14:00 - 15:00

Abstract:

A driven fan that spins to create a flow of air would conversely rotate, if we turn it off, and subject it to a strong external flow. This is a classic example of reciprocity between cause and effect, in a life scale experiment. In small scale hydrodynamics, however, when the Reynolds number is quite low, a swimmer (pump) would generate a net motion (flow) only if its constructing parts non-trivially follow a pattern of motion which breaks time reciprocity. Here, considering a simple and well-controlled system of two micron-sized beads, we investigate if the mentioned exchange of physical cause and effect also holds at the low Reynolds number situations. Two suspending microbeads, each held by an optical trap, are subjected to an external fluid flow. Apart from their local fluctuations, the two beads interact with each other through hydrodynamic interactions. We successfully verify that the external flow, causes the two beads to imitate the very motion they had when intended to produce a net fluid flow. Extending this exploration to a chain of many beads, i.e. a flexible polymer, we successfully confirm that the aforementioned reciprocity in physical causes and effect even for a more complicated system, like a polymer chain. Finally, we observe that the onset of external flow results in a non-trivial flow of heat along the chain! The coupling between fluid flow and the heat flow, leads us to investigate if Onsager’s reciprocal relations also hold for such a system of suspending beads/polymer in an external fluid flow.



Date: Wednesday, September 16, 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)

16 SEP 2020
16:00 - 19:00

.