22 JUN 2022
14:00 - 15:00

Scientific computing is a broad, multidisciplinary area that encompasses mathematics, computer science, and applications in science and engineering. This area makes use of the techniques of applied mathematics and computer science for the solution of scientific and engineering problems which are modeled by some differential equations. More recently, solving differential equations via learning methods emerged as a potentially new sub-field under the name of Scientific Machine Learning (SciML). This work advocates a fruitful synergy between machine learning and classical computational physics that has the potential to enrich both fields and lead to high-impact developments. In this talk, we review some learning methods such as support vector machines and neural networks that lead to some numerical learning approaches. The support vector machine model for classification tasks can be modified for the regression problems. Neural networks as well as deep networks can also be used to efficiently approximate a function, derived from the universal approximation theorems.

To get more information about the Combinatorics and Computing Weekly Seminar and webinars Zoom link, join the following google group:
https://groups.google.com/g/ipmccs

22 JUN 2022
16:00 - 17:00

Singular integral operators are among important tools in harmonic analysis. In this talk, I will discuss the history and origins of these operators and give some examples. I will also describe the so-called ``Weight theory'' with an overview of some recent results on this subject.

To get more information about the colloquium, join the following google group:
https://groups.google.com/g/ipm-math-colloquium

22 JUN 2022
15:30 - 17:30

We introduce the discontinuity problem and we prove that under the axiom of determinacy it is actually the weakest discontinuous problem in the topological Weihrauch lattice. We also discuss algebraic properties of the discontinuity problem, such as the fact that it parallelizes to the non-computability problem. We also introduce an operation that we call stashing and show that is dual to parallelization. We show that the discontinuity problem is the stashing of LLPO and several variants of it.

Zoom info:
https://us02web.zoom.us/j/83113646825?pwd=NVpsdERQSXkxWk9McXc1eFFISFc4QT09
Meeting ID: 831 1364 6825
Passcode: 365815

22 JUN 2022
11:00 - 12:00

We have performed the leading order perturbative calculation to obtain the equation of state (EoS) of the strange quark matter (SQM) at zero temperature under the magnetic field $B = 10^{18} G$. The SQM comprises two massless quark flavors (up and down) and one massive quark flavor (strange). Consequently, we have used the obtained EoS to calculate the maximum gravitational mass and the corresponding radius of the magnetized strange quark star (SQS). We have employed two approaches: the regular perturbation theory (RPT) and the background perturbation theory (BPT). In RPT, the infrared (IR) freezing effect on the coupling constant has not been accounted for, while this effect has been included in BPT. We have obtained the value of the maximum gravitational mass to be more than three times the solar mass. The validity of isotropic structure calculations for SQS has also been investigated. Our results show that the threshold magnetic field from which an anisotropic approach begins to be significant lies in the interval $2 \times 10^{18} G < B < 3 \times 10^{18} G$. Furthermore, we have computed the redshift, compactness, and Buchdahl-Bondi bound of the SQS to show that this compact object cannot be a black hole.
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Meeting Link

https://meet.google.com/esn-nyvq-dmo
https://indico.hep.ipm.ir/e/jSedaghat

22 JUN 2022
15:30 - 17:00


Abstract:
It is widely believed that consciousness presents a “hard problem”, different in kind from those posed by other aspects of the mind, such as memory or attention. A huge amount of philosophical work has been devoted to this problem. But does consciousness really present such an intractable problem? Or is the problem an imaginary one, created by the way philosophers think about consciousness? What exactly is it that we are trying to explain with a theory of consciousness? This webinar will introduce these issues and suggest that, although consciousness certainly presents many explanatory problems, it doesn’t pose the single, hyper-difficult problem that many philosophers think it does.

22 JUN 2022
13:30 - 15:00

We consider an inflationary scenario in which the two major fluid components of the early Universe, the scalar field, and the photon gas, say radiation fluid, evolve with distinct four velocities. This cosmological configuration is equivalent to a single anisotropic fluid, expanding with a four-velocity that is a combination of the two-fluid four velocities. The energy density of a single cosmological fluid is larger than the sum of the energy densities of the two inflating cosmological fluids and contains a correction term due to the anisotropy generated by the differences in the four velocities. We obtain the gravitational field equations of the non-comoving scalar field-radiation mixture for a Bianchi type I geometry. By assuming the decay of the scalar field, accompanied by a corresponding radiation generation, we formulate the basic equations of the inflationary model in the presence of two non-comoving components. By adopting the slow-roll approximation the theoretical predictions of this inflationary scenario with non-comoving scalar field and radiation fluid are compared in detail with the observational data obtained by the Planck 2018 satellite in two different dissipative limits, and constraints on the free parameters of the model are obtained. The functional forms of the scalar field potentials compatible with the non-comoving nature of this interacting model of inflation are also obtained. In the next step, By assuming that the non-comoving motion of the scalar field and radiation fluid induces small perturbations in the homogeneous and isotropic Friedmann-Lemaitre-Robertson-the anisotropy parameter is small, and the equations of the cosmological perturbations due to the non-comoving nature of the scalar field and radiation are obtained. The time evolution of the metric perturbations is explicitly obtained for the cases of the exponential and power-law background cosmological expansion.

To join the seminar, please click on the following link


https://www.skyroom.online/ch/soa/weekly-seminar


Then click on the guest button to participate

This seminar is open to the public

22 JUN 2022
14:00 - 15:00

Date: Wednesday, June 22, 2022
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 a guest.

Abstract:
Providing an optimal path to a quantum annealing algorithm is key to find good approximate solutions to computationally hard optimization problems. Reinforcement is one of the strategies that can be used to circumvent the exponentially small energy gaps of the system in the annealing process. We take a local entropy in the configuration space for the reinforcement and apply the algorithm to a number of easy and hard optimization problems.

21 JUN 2022
14:00 - 15:00


Date and time

Tuesday, 21st of June 2022 (31st of Khordad, 1401), 2:00 pm (Tehran zone)


Link

https://us02web.zoom.us/j/83538126663?pwd=VTNQWVpOdDZ1ajAvbVI1WklKODZGUT09

Meeting ID: 835 3812 6663
Passcode: 785277


Abstract

In this talk, after a brief review of the origin of axion-like particles (ALPs), I will show how charged lepton-flavor-violating (LFV) decays of the tau lepton (if exist) with an ALP in the final state can be probed at a future muon collider. I will explain the search scenario, challenges and strategies for mitigating the background. Finally, we will compare the expected constraints on the LFV couplings obtained in this analysis with the present experimental constraints.