22 APR 2021
11:00 - 12:00

We have around 170 million registered small molecules in the world. These small molecules potentially can interact with around 20,000 protein targets available in human body to modify their biological function and hopefully cure diseases. However, due to large search space, discover the right compound that bind to the right protein target is a daunting task. In recent years, using artificial intelligence (AI) has been successfully applied in almost every stage of the drug discovery project to speed up the process of research and reduce the cost and risk of failure. In this talk we will discuss potential applications of AI in different stages of the drug design pipeline from identify protein targets associated with a disease to evaluate a compound in clinical trial.

22 APR 2021
11:00 - 13:00

For a graded ideal $I$ of a polynomial ring $S=K[x_1,ldots,x_n]$ over a field $K$, the Cohen-Macaulayness of the ring $S/I$ may depend on the characteristic of the base field $K$ in general. Even when $I$ is the edge ideal of a graph, this is the case. Nevertheless, for some families of graphs like chordal graphs and K"onig graphs, the Cohen--Macaulay property of the edge ideal $I(G)$ has combinatorial descriptions which means that it is independent of the base field. In this talk, inspired by the notion of K"onig graphs, we introduce graded ideals of K"onig type with respect to a monomial order $<$. It turns out that if $I$ is of K"onig type, then the Cohen--Macaulay property of $ini_<(I)$ does not depend on the characteristic of the base field. This happens to be the case also for $I$ itself when $I$ is a monomial ideal or a binomial edge ideal. We consider the ideals of K"onig type among the edge ideals, binomial edge ideals and the toric ideal of a Hibi ring and use the König property to determine explicitly their canonical module.
This is based on a joint work with Jürgen Herzog and Takayuki Hibi

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21 APR 2021
13:30 - 15:00

Abstract
The XENON1T collaboration recently reported the excess of events from recoil electrons which may be sign of a fundamental new discovery about our universe. In this talk, I will review the current status of different dark matter (DM) direct detection experiments towards ultimate DM detector. I will show that sterile neutrinos with masses around 90 keV and specific effective coupling can explain the XENON1T anomaly preserving DM astrophysical and cosmological constraints, and it possibly describes the anomalies in other experiments. At the end I will try to explain how one can be convinced that DM has been discovered or not from observing an unexplained excess?
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20 APR 2021
15:00 - 16:00

Abstract:

The LIGO discovery of the gravitational waves from merging of the binary of black holes (BH) has revitalized interests in the primordial black holes (PBH) as the dark matter candidates. One of the mechanism of generation of these PBHs is the collapse of large overdensities during radiation dominated phase. Inflation is a prime candidate for generation of density perturbations. However the typical magnitude of fluctuation generated during inflation at the CMB scales is very small. In the first part of this talk I will describe a mechanism for generation of such large amplitude fluctuations during inflation. The mechanism is based on the formalism of Extended EFT of inflation (EEFToI) with the sixth order polynomial dispersion relation for scalar perturbations. The instability mechanism needs to be arranged to kick in at the scales of interest which is related to the mass of the PBHs one would like to produce. In the second part of the talk, I will focus on another mechanism of PBH formation during inflation, namely the nucleation of domain walls during inflation. I explicitly construct a double field inflationary model, which satisfies the latest PLANCK constraints at the CMB scales and produces the whole dark matter energy density as primordial black holes (PBHs), in the mass range 10^{-17}-10^{-13} solar mass. Obtaining PBHs in this mass range enforces the scale of inflation to be extremely low, which makes the efforts to observe gravitational waves at the CMB scales futile. However, it is high enough to allow for a successful Big Bang Nucleosynthesis (BBN). Instead, exit from the rolling metastable direction to the true vacuum of the potential may happen with a first-order phase transition (PT) that leaves behind a stochastic gravitational wave background (SGWB), which is potentially observable by LISA. We show that PBHs produced during such a first-order PT from the collision of bubble walls contribute negligibly to the PBH mass spectrum. Examining the mass distribution of PBHs and possible SGWB from the end of inflation, we may be able to gain invaluable information about the topography of the landscape in our neighborhood.




Date: Tuesday, April 20th

3 p.m. - 4 p.m. (Tehran time)

Unusual time



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Meeting ID: 884 3079 2016

Passcode: 395721

19 APR 2021
16:00 - 18:00

Theory of Conflictless Drama in Soviet Literature


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

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15 APR 2021
11:00 - 13:00

Schubert Derivations are distinguished instances of Higher Order (or Hasse-Schmidt) derivations on exterior algebras [8], originally introduced to phrase Schubert Calculus for Grassmannians varieties, solely in terms of Leibniz rules and integration by parts. The purpose of the talk is showing their applications to find explicit vertex operators representations of Lie algebras of endomorphisms on exterior algebras and related spaces [1, 2, 3, 4], like the infinite wedge power (as in [9] and the bosonic Fock space (a polynomial ring in infinitely many indeterminates). This is related with some pioneering work done by Date, Jimbo, kashiwara and Miwa at the beginning of the Eighties [5]. The premises are the following two elementary observations: each vector space is a representation of the Lie algebra of its own endomorphisms and the r-th exterior power of a polynomial ring in one indeterminate is isomorphic to a polynomial ring in r indeterminates.
References
[1] O. Behzad, Hasse-Schmidt Derivations and Vertex Operators on Exterior Algebras. Ph.D. Thesis, IASBS, Zanjan, 2021;
[2] O. Behzad, A. Contiero, L. Gatto, R. Vidal Martins, Polynomial ring representation of endomorphisms of exterior powers. Collectanea Math., 2021 (to appear), ArXiv:2005.01154.pdf,
[3] O. Behzad, L. Gatto, Bosonic and Fermionic Representations of Endomorphisms of Exterior Algebras, Fundamenta Math. 2021 (to appear), ArXiv:2009.00479.pdf

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15 APR 2021
11:00 - 12:05

Abstract: Very recently, the LHCb collaboration @ CERN and muon g-2 collaboration @ Fermilab have announced their results on the lepton flavor universality violation (LFUV) and muon magnetic dipole moment, which deviate from the SM theory predictions by 3.1 and 4.2 standard deviations, respectively. In this talk we address these results and talk about their meanings and possible scenarios to explain the observed deviations if they are confirmed.



http://meet.google.com/iys-ixfq-gwm

14 APR 2021
16:30 - 17:30

The Eigenvalue Theorem is a basic result in computational algebraic geometry. It says that solving a zero-dimensional system of polynomial equations can be reduced to an eigenvalue problem in linear algebra. The name of Ludwig Stickelberger (1850-1936) is often attached to this theorem, yet papers that use his name never cite any of his papers. My lecture will explore the reasons for this. The answer involves a lovely trace formula in algebraic number theory and an algebra textbook published by Gunter Scheja and Uwe Storch in 1988.
To get more information about the colloquium, join to the following google group:
https://groups.google.com/g/ipm-math-colloquium

14 APR 2021
11:00 - 12:00

Abstract: We study the dynamics of electroweak phase transition in a simple extension of the Standard Model where the Higgs sector is extended by adding an $SU(2)_L$-mutiplet. By making random scans over the parameters of the model, we show that there are regions consistent with constraints from collider experiments and the requirement for a strong first-order electroweak phase transition which is needed for electroweak baryogenesis. Further, we also study the power spectrum of the gravitational waves which can be generated due to the first-order phase transitions. Observation of such gravitational waves, such as by future space-based gravitational wave detectors, could yield information that is complementary to collider and dark matter experiments.


Indico: https://indico.particles.ipm.ir/indico/event/408
https://meet.google.com/hkp-tout-qzi

14 APR 2021
16:30 - 18:00

Abstract:
Axions and Axion-like fields are popular in cosmology, both as the inflaton and as dark matter. Such fields can naturally condense into long-lived, spatially localized configurations (oscillons, axion stars etc). I will discuss conditions under which such solitons become effective antennas for electromagnetic radiation by converting axions to photons, which can lead to potential observational signatures. I will also discuss multimessenger signals: electromagnetic and gravitational wave emission from soliton collisions. Time permitting, I will digress to advertise a separate topic of CMB birefringence from a different type of soliton: string loops in ultralight-axions.
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13 APR 2021
14:00 - 15:00

Abstract:

Recent developments on black holes have shown that a unitarity-compatible Page curve can be obtained from an ensemble-averaged semi-classical approximation. In this talk, we emphasize (1) that this peculiar manifestation of unitarity is not specific to black holes, and (2) that it can emerge from a single realization of an underlying unitary theory. To make things explicit, we consider a hard sphere gas leaking slowly from a small box into a bigger box. This is a quantum chaotic system in which we expect to see the Page curve in the full unitary description, while semi-classically, eigenstates are expected to behave as though they live in Berry's ensemble. We reproduce the unitarity-compatible Page curve of this system, semi-classically. The computation has structural parallels to replica wormholes, relies crucially on ensemble averaging at each epoch, and reveals the interplay between the multiple time-scales in the problem. Working with the ensemble averaged state rather than the entanglement entropy, we can also engineer an information "paradox". Our system provides a concrete example in which the ensemble underlying the semi-classical Page curve is an ergodic proxy for a time average, and not an explicit average over many theories. The questions we address here are logically independent of the existence of horizons, so we expect that semi-classical gravity should also be viewed in a similar light.



Date: Tuesday, April 13th

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

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Meeting ID: 884 3079 2016

Passcode: 395721

12 APR 2021
11:00 - 12:00

Based on
https://arxiv.org/abs/2101.05095


Abstract: This article presents a new set of proton parton distribution functions, ATLASepWZVjet20, produced in an analysis at next-to-next-to-leading order in QCD. The new data sets considered are the measurements of W+ and W− boson and Z boson production in association with jets in pp collisions at √ s =8 TeV performed by the ATLAS experiment at the LHC with integrated luminosities of 20.2 fb−1 and 19.9 fb−1, respectively. The analysis also considers the ATLAS measurements of differential W and Z boson production at √ s =7 TeV with an integrated luminosity of 4.6 fb−1 and deep-inelastic-scattering data from e p collisions at the HERA accelerator. An improved determination of the sea-quark densities at high Bjorken x is shown, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range x≲0.02 found by previous ATLAS analyses.


meet.google.com/mim-xppw-ncq

7 APR 2021
11:00 - 12:00

Abstract: In the collision of heavy ions, due to the fast-moving charged particles, a strong magnetic field of the order of 10^{18-20} Gauss is expected to be generated. In the presence of such a strong magnetic field, several novel phenomena like Magnetic catalysis of chiral symmetry restoration, the chiral magnetic effect may arise. Therefore, the knowledge of the evolution of the magnetic field, its lifetime, and possible effects on the plasma is of primary interest.
In this talk, I start with a short overview of the properties of the generated magnetic field. Then I will consider the interaction of the spin of the constituent particles with the background magnetic field. This leads to a finite magnetization. Finite magnetization causes anisotropy in the pressure of the system. In this case, using the quantum kinetic theory the effect of finite magnetization on the evolution of plasma will be discussed.. Finally, I will present part of the results obtained in Phys.Rev.D 101 (2020) 7, 076022.


Indico: https://indico.particles.ipm.ir/indico/event/407

7 APR 2021
13:30 - 15:00

Abstract:
Filamentary structures are omnipresent in the cold interstellar medium. They are found both in star-forming and non-star-forming regions. It has been revealed that these filaments are the hosts of early stages of formation of stars, so their study provides key insight to understand how do stars form? In this talk, I will try to briefly discuss this new filamentary paradigm of star formation and present some of our recent works on the stability and fragmentation of filaments.
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