IPM Calendar 
Saturday 25 June 2022   Today  
Events for day: Wednesday 15 December 2021    
           11:00 - 12:00     Wednesday Weekly Seminar - google meet
Relativistic second-order dissipative hydrodynamics from Zubarev's non-equilibrium statistical operator


Abstract: We present a new derivation of relativistic second-order dissipative hydrodynamics for quantum systems using Zubarev's non-equilibrium statistical-operator formalism. This is achieved by a systematic expansion of the energy-momentum tensor and the charge currents to second order in deviations from equilibrium. As a concrete example, we obtain the relaxation equations for the shear-stress tensor, the bulk-viscous pressure, and the charge-diffusion currents required to close the set of equations of motion for relativistic second-order dissipative hydrodynamics. We also identify new transport coefficients which describe the relaxation ...

           13:30 - 15:00     Weekly Seminar (Online)
Primordial Gravitational Waves, Primordial Black Holes and Lepton Asymmetry


We have investigated the effect of thermal history of the early Universe on the spectrum of primordial (and induced) gravitational waves (PGW) background and the mass distribution (and the threshold) of primordial black holes (PBH) formation. Also, we studied the imprint of nonvanishing lepton flavor asymmetry on the thermal bath possibly leading to the formation of pion condensation around the QCD transition epoch. These will cause observable effects on the PGW and PBH. These predictions can be constrained/observed using gravitational wave observatories like LIGO, LISA and other earth/space based missions. ...

           14:00 - 15:00     Weekly Seminar
PT-symmetry optical waveguides


PT-symmetry has become an active research area, when Bender and Boettcher showed that a wide class of non-Hermitian Hamiltonians can exhibit real spectra if they commute with the PT operator. Mathematical analogy between the Schrodinger equation and the paraxial Helmholtz wave equation initiated intensive studies for implementing PT-symmetry on optical platforms, where the non-hermiticity can be tailored with optical gain and loss. Coupled optical waveguides provide an ideal platform for investigation of PT-symmetry systems. In this talk, after a short review of PT-symmetry concept we will focus on optical waveguides array, and introduce an i ...

           16:00 - 17:00     Quantum Computing & Quantum Information Monthly Seminar
Squeezing in Nonequilibrium Quantum thermodynamics


Squeezed-thermal states are the states with reduced thermal fluctuations in one quadrature (e.g., position) at the expense of enhanced thermal fluctuations in the other quadrature (e.g., momentum) compared to the standard thermal fluctuations at a given temperature. These states have provided an early benchmark for exploring the relation between quantum effects and thermodynamics. It is demonstrated that the efficiency of a heat engine coupled to squeezed thermal noise can surpass the standard Carnot limit. Also, one can extract mechanical work from a single squeezed thermal reservoir in a cyclic process. In this talk, I present a theoretical ...

           18:00 - 19:30     Online Seminar - Functional architecture of cerebral cortex during naturalistic movie-watching

Description :

Characterizing the functional organization of cerebral cortex is a fundamental step in understanding how different kinds of information are processed in the brain. Monumental efforts over the past decades have uncovered the function of many cortical areas in response to selected stimulus categories. However, it is still unclear how cortical areas are organized during naturalistic vision and audition. Here we used high-resolution functional MRI data from 176 human subjects to map the macro-architecture of entire cerebral cortex based on responses to a 60-minute audiovisual movie stimulus. A data-driven clu ...