1 MAY 2025
14:00 - 16:00

Intuitively, generic sampling is a method for sampling types over monster models of a first-order theory with respect to a Keisler measure. In practice, this involves studying countably iterated Morley products of relatively tame Keisler measures. Given such a measure, one can straightforwardly derive a corresponding Borel measure on the space of L-structures over the natural numbers. In particular, if the original monster model is a graph (respectively, a hypergraph), then generic sampling yields measures on the space of all graphs (respectively, hypergraphs) on the natural numbers.
A graphon is a symmetric measurable map from $[0,1]^{2}$ to $[0,1]$. These graph-like objects also give rise to a notion of sampling. It turns out that all Sym(N)-invariant measures on the space of graphs (over the natural numbers) are mixtures of sampling procedures arising from graphons. We remark that graphons admit a higher-arity generalization to hypergraphs, called hypergraphons, which exhibit a similar property.
We prove a representation theorem: (hyper)graphon sampling can be encoded within the framework of generic sampling. We remark that generic sampling in practice can give rise to non-Sym(N)-invariant measures and so generic sampling is strictly more general than what arises from (hyper)graphons. This is joint work with Nathanael Ackerman, Cameron Freer, James Hanson, and Rehana Patel.

Zoom room information:
https://us06web.zoom.us/j/81916335336?pwd=5zQT4lutMiBoY5Xp1pkFGtbqiaGozg.1
Meeting ID: 819 1633 5336
Passcode: 559618
Venue: Niavaran, Lecture Hall 1

30 APR 2025
11:00 - 12:00

Abstract:

Interest of the research in terahertz (THz) wave has been strongly motivated by its wide applications in the fields of physics, chemistry, biology, and engineering. Developing efficient and reliable THz source is of uttermost priority in these researches. Generally, due to the restrictions mainly caused by laser damage threshold, it is not possible to generate efficient and strong THz radiation. Plasma is a quasi-neutral medium composed of electrons and positive ions, exhibiting long-range collective behavior. It has garnered significant attention as a promising source for generating THz electromagnetic wave, primarily due to the ease with which it can tolerate very high power laser and provide strong THz beams in comparison with other media. This review focuses on the various key aspects of THz mechanisms in laser-plasma interactions and also examines the characteristics of the emitted THz waves under different laser and plasma parameters. Harnessing the advancements in ultrafast pulses, laser-induced plasma has proven to be a promising tool for generating THz waves.

Indico Link:
https://indico.hep.ipm.ir/e/s.safari

Link to Join Virtually:
https://www.skyroom.online/ch/ipm-particles/weekly-seminar

30 APR 2025
14:00 - 15:00

Predicting drug-target interactions (DTIs) has become a significant issue in bioinformatics, as it represents a crucial initial step in drug repositioning. Consequently, researchers are working to develop more accurate computational methods for DTI prediction. These methods are typically based on machine learning or recommender systems and incorporate biological and chemical information to enhance prediction accuracy. A fundamental assumption underlying these approaches is that drugs with similar chemical structures are likely to share similar targets. Therefore, chemical similarity between drugs is integrated into computational methods to improve prediction performance. However, this raises an important question: Is this assumption valid? If so, what is the most appropriate method for calculating drug-drug chemical structure similarities? Furthermore, does the inclusion of such similarity information enhance the performance of all DTI prediction methods equally? In this study, we examined the extent to which incorporating drug-drug chemical structure similarities improves DTI prediction. To achieve this, we evaluated different types of real chemical similarities, randomly generated drug-drug similarities, four benchmark datasets, and four state-of-the-art prediction methods. Our findings indicate that factors such as dataset characteristics, the specific prediction method used, and the algorithm employed for calculating chemical similarities all play a critical role. Thus, it cannot be conclusively stated that the inclusion of drug-drug similarity information consistently leads to significant improvements in prediction outcomes.


This Seminar is free, hybrid, and open to the public.

30 APR 2025
14:00 - 15:00

Imagine a game played between two players, Maker and Breaker, on an infinite complete graph G. The players alternately claim edges of G, beginning with Maker, and play continues forever. Maker's aim is that by the end of the game she should have claimed all edges of an infinite complete subgraph of G, and Breaker's aim is to prevent this. I will discuss a number of simple variants of this game and examine who has a winning strategy in each case.

Zoom room information:
https://us06web.zoom.us/j/84906984159?pwd=BCWaIbXBuku3A5I84zNg9mHFxVZjXD.1
Meeting ID: 849 0698 4159
Passcode: 362880
Venue: Niavaran, Lecture Hall 1

30 APR 2025
13:30 - 15:00

30 APR 2025
17:30 - 19:00

Let $X$ be a smooth connected projective $K3$ surface over the complex numbers and let $Spl(r; c_1, c_2)$ be the moduli space of simple sheaves on $X$ of fixed rank $r$ and Chern classes $c_1$ and $c_2$. In 1984, Mukai proved that $Spl(r; c_1, c_2)$ is a smooth algebraic space of dimension $2rc_2-(r-1)c_1^2-2r^2+2$ with a natural symplectic sstricture, i.e., it has a non-degenerate closed holomorphic 2-form. In my talk, I will present a useful method to construct isotropic and Lagrangian subspaces of $Spl(r; c_1, c_2)$. This is joint work with Barbara Fantechi.

https://zoom.us/join
Meeting ID: 9086116889
Passcode: 362880
Website: http://math.ipm.ac.ir/agnt/
Venue: , (Online)

30 APR 2025
18:00 - 19:00

Kahler Calabi-Yau threefolds can be deformed into a non-Kahler object by degeneration and resolution. We will discuss various aspects of the geometrization of this process by special non-Kahler metrics.
This is joint work with T. Collins and S.-T. Yau.

google meet's link:
https://meet.google.com/rtm-twkv-ury
Venue: , (Online)

29 APR 2025
13:30 - 15:30

Predictions enable top-down pattern separation in macaque face processing hierarchy - Journal Club

29 APR 2025
14:00 - 15:00

Date and time

Tuesday, April 29th, 2025 (9 Ordibehesht), 2:00 pm (Tehran zone)




Link

https://www.skyroom.online/ch/schoolofphysics/highenergyseminar


Abstract
I will show that spontaneous CP violation, automatically realized in theories with modular invariance, offers a novel solution to the strong CP problem (arXiv:2305.08908, arXiv:2406.01689). I will then show that the cosmological evolution of the CP-breaking scalar modulus can drive baryogenesis (arXiv:2504.03506). Finally, I will present a distinctive signal of these heavy gravitational scalars: their cosmological decays into gravitons generate gravitational waves that today redshift to optical frequencies (arXiv:2501.16427).

28 APR 2025
11:00 - 12:00

Abstract:

The CMS-TOTEM Precision Proton Spectrometer (PPS) is a CMS subdetector operating at the Large Hadron Collider (LHC) installed at a distance of ~200-220 meters from the CMS central detector. PPS measures the kinematics and time-of-flight of protons scattered in the very forward region with high precision. In this talk, I will explain how the PPS data is used to reconstruct protons at the interaction point and how it helps study Central Exclusive Production (CEP) processes.

Based on:
arXiv:2210.05854 and arXiv:2211.16320.

Meeting Place:
Seminar Room, School of Particles and Accelerators, IPM

Link to Join Virtually:
https://www.skyroom.online/ch/ipm-particles/journal-club

23 APR 2025
09:00 - 16:00

This workshop will delve into the fundamental principles and recent progress in light-matter interactions, with a special emphasis on quantum coherence and interference. These concepts are essential for understanding quantum optical phenomena, which have far-reaching implications for quantum computing, precision metrology, and advanced photonic technologies. Participants will explore computational and numerical approaches to studying light-matter interactions, gaining insights into theoretical frameworks and practical implementations. A key focus will be on the ways in which coherent optical effects can be precisely controlled through the modulation of coupling fields, enabling novel functionalities in quantum photonic systems.

23 APR 2025
16:00 - 17:00

This lecture is intended as an introduction to some of the metaphysical and epistemological issues that are usually raised in connection with mathematical thought. These issues include, among other things, the nature of abstract objects like numbers and sets, some of the well-known arguments for the existence of such objects as well as the epistemological problems that the existence of those objects incur. There will also be some brief discussions of certain anti-realist approaches to mathematical ontology.

Subscribing the Mathematics Colloquium mailing list:
https://groups.google.com/g/ipm-math-colloquium
Venue: Niavaran, Lecture Hall 1

23 APR 2025
14:00 - 15:00

‎Let A=[a_₀, a_₁, ..., a_{n-1}] ∈ ℂ^ℓ be a finite complex sequence of length ℓ periodically continued with period ℓ. ‎The periodic autocorrelation function PAF(A,s) of A at lag s is‎ PAF(A, s) =∑ {j=0}^{ℓ-1} a_joverline{a_{j+s}}, s=0,1, ..., ℓ-1. ‎Two sequences‎ ‎A and B of the same length ℓ. ‎form a Legendre pair (A,B) if‎ ‎PAF(A,s)+PAF(B,s)=-2, s=1,2, ?, ⌊n/2⌋. ‎Binary Legendre pairs of length ℓ are pertinent to the construction of Hadamard matrices of order ℓ +2 which can exist only if ℓ is odd‎. ‎It is conjectured that there is a binary Legendre pair of every odd length ℓ which is stronger than the Hadamard-matrix conjecture‎. ‎Several infinite classes of Legendre pairs are known‎. ‎The most prominent constructions are defined via characters of finite fields‎. ‎In particular‎, ‎there are Legendre pairs of length ℓ for every prime ℓ =p and every Mersenne number ℓ =2^s-1‎, ‎respectively‎. ‎The smallest undecided case is ℓ=11. ‎In the first part of the talk we summarize the known results on binary Legendre pairs‎. ‎In the second part we discuss quaternary Legendre pairs of length ℓ‎. ‎In contrast to binary Legendre pairs they can exist for even ℓ as well‎. ‎Very recently‎, ‎the first infinite construction was found by Jedwab and Pender completing our earlier semi-construction‎. ‎We give also constructions of quaternary Legendre pairs of length ℓ for all remaining even ℓ < 42‎. ‎The smallest open case is ℓ =42 and the case ℓ =46 is particularly interesting since the existence of a quaternary Legendre pair of this length would imply the existence of a quaternary Hadamard matrix of order 94. ‎Finally‎, ‎we mention generalizations to k-ary sequences‎.

Zoom room information:
https://us06web.zoom.us/j/84906984159?pwd=BCWaIbXBuku3A5I84zNg9mHFxVZjXD.1
Meeting ID: 849 0698 4159
Passcode: 362880
Venue: Niavaran, Lecture Hall 1