16 JUL 2025
14:00 - 15:00

We study the impact of noise on the dynamics of entanglement in the transverse-field Ising chain, with the field quenched linearly across one or both of the quantum critical points of the model. Taking concurrence as a measure of entanglement, we find that a quench generates entanglement between nearest- and next-nearest-neighbor spins, with noise reducing the amount of entanglement. Focusing on the next nearest-neighbor concurrence, known to exhibit Kibble-Zurek scaling with the square root of the quench rate in the noiseless case, we find a different result when noise is present: The concurrence now scales logarithmically with the quench rate, with a noise-dependent amplitude. This is also different from the anti-Kibble-Zurek scaling of defect density with quench rate when noise is present, suggesting that noisy entanglement generation is largely independent from the rate of defect formation. Intriguingly, the critical time scale beyond which no entanglement is produced by a noisy quench scales as a power law with the strength of noise, with the same exponent as that which governs the optimal quench time for which defect formation is at a minimum in a standard quantum annealing scheme.

Based on : https://doi.org/10.48550/arXiv.2503.03584


Venue: Room D, 3rd Floor, Farmanieh Building, IPM
Link: https://vmeeting2.ipm.ir/b/nan-gkn-wmh-exh

16 JUL 2025
11:00 - 12:00

Abstract:

Understanding the fundamental nature of dark matter remains one of the most profound challenges in modern physics. In this talk, I will present how cosmic birefringence—the rotation of the polarization plane of Cosmic Microwave Background (CMB) photons—can serve as a sensitive probe of dark matter phenomenology. I will focus on theoretical frameworks in which dark matter candidates, such as sterile neutrinos, dipolar dark matter, or axion-like fields, induce parity-violating effects that manifest as measurable birefringence. These signatures offer a unique observational window into the interactions between dark matter and Standard Model particles, providing constraints that are complementary to those from conventional direct and indirect detection methods.

Indico Link:
https://indico.hep.ipm.ir/e/Mahmoudi


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

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

15 JUL 2025
14:00 - 15:00

Date and time

Tuesday, July 15th, 2025 (24 Tir), 2:00 pm (Tehran zone)




Link

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


Abstract

In this talk, I will explain a model of warm inflation driven by axion-like particles interacting with $U(1)$ gauge fields, with implications for the early universe's thermal evolution. By extending traditional warm inflation models, we introduce a dissipation mechanism through the thermal fluctuations of electromagnetic fields, leading to a non-trivial backreaction on the inflaton's dynamics. Our results are consistent with CMB observations, even for a natural sub-Plankian Axion decay constant $f

14 JUL 2025
11:00 - 12:00

Abstract:

There is a wide variety of fixed points in many-body quantum systems, including thermal and non-thermal fixed points. These fixed points are characterized by specific exponents and scaling relations. Recently, it has been proposed that relativistic hydrodynamic equations can describe the evolution of fluctuations near non-thermal fixed points far from equilibrium. In this talk, we will first review some fundamental concepts of fixed points and their emergence through renormalization group equations. We will then explore the hydrodynamic equations applicable to these cases.

Based on:
https://doi.org/10.48550/arXiv.2504.18754

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

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

25 JUN 2025
18:00 - 19:30

Date and time,


6-7:30pm, Wednesday 25 June 2025 (4 Tir 1404)


Venue: Online



Link

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



Abstract


Gamma Ray Bursts (GRBs) and Cosmic Rays (CRs) are easily understandable. Solid observations of quasars and micro-quasars show how these objets emit “Cannonballs” (CBs), though the underlying mechanisms are not theoretically well understood. The assumption that core-collapse supernovae emit CBs plus some trivial relativistic kinematics provide a successful understanding of GRBs and CRs. The self-defined “official experts” on these fields resist the evidence, in an explicitly inquisitorial way.

16 JUN 2025
16:00 - 18:00

Some Considerations on the Internal Approach to Interpreting Physical Theories

15 JUN 2025
16:00 - 17:30

12 JUN 2025
14:00 - 16:00

The automorphism group of a countable first-order structure naturally carries the topology of pointwise convergence. In certain cases, this topology can be used to recover/reconstruct the structure up to bi-interpretability. However, it is not the only group topology of interest. In this talk, we explore various group topologies on automorphism groups - particularly minimal group topologies - with a special emphasis on the Zariski topology. This is joint work with Javier de la Nuez González.

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

11 JUN 2025
11:00 - 12:00

Abstract:

In this talk, I will present a series of studies where I explore the quantum properties of gravitational cats (so-called gravcats) modeled by interacting qubits under a variety of physical conditions. My focus is on understanding how gravcats can preserve quantum correlations in the presence of thermal noise, gravitational interactions, and different environmental decoherence mechanisms. I then extend this investigation to more general environments, including classical stochastic, correlated dephasing channels, and power-law noise, as well as weak measurement interventions. These results show that gravcats serve as robust resources for maintaining quantum correlations, particularly in non-Markovian regimes where information backflow can delay decoherence. Altogether, these works contribute new insights into how gravcats can function as reliable carriers of quantum information and highlight the nuanced interplay between gravity, noise, and quantumness in open quantum systems.


Based on:
1. https://journals.aps.org/prd/abstract/10.1103/PhysRevD.111.064077
2. https://www.nature.com/articles/s41598-025-03593-5
3. https://link.springer.com/article/10.1140/epjc/s10052-024-13034-8


Indico Link:
https://indico.hep.ipm.ir/e/S.Haddadi1

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

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

11 JUN 2025
14:00 - 15:00

In this presentation, we will study the spatially dependent of the coherent optical phenomena in quantum systems. Here, we will discuss the electromagnetically induced grating via optical composite vortex light in a four-level N-type atomic system. We will show that by controlling the orbital angular momentum of the optical vortex light the diffraction pattern of the Fraunhofer diffraction can be controlled in different regions of the space. Moreover, we will study the spontaneous emission (SE) spectrum of the quantum system in two different quantum systems via optical vortex light. In the first one, we will discuss the spatial pattern of the spontaneous emission spectrum in a four-level atomic system located in free space and in the second one, we will analyze the SE spectrum of a double V-type atomic system located near plasmonic nanostructure.


Venue: Room D, 3rd Floor, Farmanieh Building, IPM
Link: https://vmeeting2.ipm.ir/b/nan-gkn-wmh-exh

11 JUN 2025
14:00 - 15:00

Rank aggregation is a well studied algorithmic problem where, given a set of input preference lists over a set of items, the objective is to compute a single ranking that best summarizes the individual lists. The problem has numerous applications, e.g., in social choice, recommendation systems, and information retrieval. In this talk we tackle this problem in the dynamic setting, and present a practically efficient 2-approximation algorithm with near linear update time for the problem. Based on joint work with Alireza Zarei and Morteza Alimi.

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

11 JUN 2025
16:00 - 18:00

Is Voluntarist Epistemology Useful for Philosophical Debates?