سخنران: دکتر فرید تقی نواز (پژوهشگاه دانشهای بنیادی)

18 خرداد 1402
11:00 تا 12:00

سری هیدرودینامیک در سامانه های بحرانی

سخنران: علی خزلی, دانشگاه اینریا، فرانسه

17 خرداد 1402
16:00 تا 17:00

در این ارائه به معرفی اجمالی زمینه های تحقیقاتی و دستاوردهای پژوهشی خود می پردازم. ابتدا به پژوهش ها در زمینه فرآیندهای نقطه ای پایا و گراف های تصادفی تک پیمانه ای (unimodular) و ارتباط بین آن ها می پردازم. عامل کلیدی ارتباط این مفاهیم، فرمولی به نام اصل انتقال جرم است که با صورت های مختلف اما مشابهی در مفاهیم یاد شده وجود دارد. این اصل باعث ارتباط با مفاهیم و شاخه های دیگری از ریاضیات نیز می شود؛ مانند حد گراف ها، نظریه گروه ها، سیستم های دینامیکی حافظ اندازه، عمل حافظ اندازه گروه، و روابط هم ارزی بورل. همچنین در مورد پژوهش های دیگر خود صحبت می کنم، به طور خاص، اثبات ارگودیک بودن یک مدل احتمالاتی و پژوهش هایی در مورد فضاهای غیر گسسته، مانند حد تجانسی (scaling limit) فضاهای گسسته، فضاهای متریک تصادفی، و مقاله هایی در حوزه هندسه متریک و تعمیم متریک گروموف-هاسدورف.

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سخنران: حسن خدایی مهردانشگاه خواجه نصیرالدین طوسی

17 خرداد 1402
14:00 تا 15:00

Quantum computing has emerged as a highly promising paradigm for tackling intricate computational problems. Nevertheless, the delicate nature of quantum information presents substantial obstacles in upholding the integrity of quantum states during computation. To address this challenge, quantum error correction techniques, specifically stabilizer codes, have a vital role in mitigating errors and preserving quantum information. In this presentation, we delve into the fundamental
concepts of quantum stabilizer codes and their intricate connection to
lattice structures. These codes are characterized by their stabilizer generators, which form an Abelian group and facilitate error detection through commutation relations. We further explore the significance of employing lattice-based approaches in the design and construction of quantum codes.





Gharar link :

https : //room.gharar.ir/ba05e1ad − 99f6 − 4911 − b60e − dbf02616a692

سخنران: جی هان پارکمرکز هندسه و فیزیک، کره جنوبی

17 خرداد 1402
13:30 تا 15:00

This talk briefly explains how to find closed simply connected Sasaki-Einstein 5-manifolds from K-stable log del Pezzo surfaces. It then lists closed simply connected 5-manifolds that are known so far to admit Sasaki-Einstein metrics. It also presents possible candidates for Sasaki-Einstein 5- manifolds to complete the classification of closed simply connected Sasaki-Einstein 5-manifolds.



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سخنران: S. PourOjaghi, School of Physics

16 خرداد 1402
14:00 تا 15:00

Date and time

Tuesday, 6th of June 2023 (16th of Khordad, 1402), 2:00 pm (Tehran zone)



Link

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



Abstract

Flat ΛCDM cosmology is specified by two constant fitting parameters in the late-time Universe, the Hubble constant H_0 and matter density $\Omega_{m0}$. While these parameters are mathematically constant, they do not need to be observationally constant unless the EoS or model accurately describes the Universe. In this work, we have shown that using observational data at different redshifts shows that the ΛCDM model parameters are redshift dependent. In other words, we have confirmed that observed data exhibit an increasing $\Omega_{m0}$ (decreasing H_0) trend with increasing redshift bins.









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

سخنران: بهروز طایفه رضایی, پژوهشگاه دانشهای بنیادی

10 خرداد 1402
16:00 تا 17:00

We discuss two notions of percolation on graphs. The first one is $r$-neighbor bootstrap percolation in which an activation process of the vertices of a given graph is carried out. The process starts with some initially activated vertices and then, in each round, any inactive vertex with at least $r$ active neighbors becomes activated. The second one is the so called graph bootstrap percolation in which we activate the edges of a graph instead of vertices. Starting with some initially activated edges, we activate any inactive edge which creates a new copy of $H$, the pattern or base graph. Two problems, one of combinatorial nature and the other of probabilistic type are reviewed. The minimum size of a set of initially activated vertices leading to the activation of all vertices of a graph $G$ in the $r$-neighbor bootstrap percolation is denoted by $m(G, r)$. Computing $m(G, r)$ is a combinatorial problem. In the second problem, each vertex of $G$ is initially activated with a probability $p$ and the question is to find the probability threshold of activation of all vertices of the graph $G$. We talk about the latest developments on both problems and also the connections between $r$-neighbor bootstrap percolation and graph bootstrap percolation.

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