August 2021

Date: August 12

Time: 09:30 IST

Speaker: Amitabh Virmani (CMI Chennai)

This talk is a part of the activities of the Center for Strings, Gravitation and Cosmology of IIT Madras

Title: Black Hole Hair Removal for N=4 CHL Models

• Abstract: The BMPV black hole in flat space and in Taub-NUT space have identical near horizon geometries but different microscopic indices. For a wide class of N=4 theories, we show that after removing the contributions of the hair modes from the microscopic partition functions, the 4d and 5d horizon partition functions agree. In this talk, I will present the hair construction, discuss supersymmetry properties of the hair, and the hair partition functions.Based on: https://arxiv.org/abs/2010.02240

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Date: August 19

Time: 09:30 IST (UTC + 5:30)

Speaker: Paolo Glorioso (Stanford University)

This talk is a part of the activities of the Center for Quantum Information Theory of Matter and Spacetime of IIT Madras

Title: Breakdown of hydrodynamics for fracton fluids below 4+1 dimensions

• Abstract: Fracton phases are characterized by having elementary excitations with restricted mobility. In the context of hydrodynamics it has been shown theoretically, and confirmed experimentally, that such restricted mobility leads to novel collective behaviors. In this talk, I will introduce the hydrodynamics of fractons with translation symmetry, focusing on the simplest case where dipole moment is the only additional conserved quantity. This hydrodynamics turns out to have rather surprising properties, owing to the fact that dipole conservation leads to a non-trivial extension of spacetime symmetries. When including renormalization effects, the low-energy theory becomes unstable at low-energy below four spatial dimensions: dipole-conserving fluids are governed not by hydrodynamics, but by a fractonic generalization of the Kardar-Parisi-Zhang universality class.

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Date: August 26

Time: 17:30 IST (UTC + 5:30)

Speaker: Sutapa Samata (IACS Kolkata)

This talk is a part of the activities of the Center for Quantum Information Theory of Matter and Spacetime of IIT Madras

Title: Study of DC and Hall resistivity for a new semi-holographic non-Fermi liquid model

• Abstract: In this talk, I shall introduce a new model for semi-holographic non-Fermi liquid. In this model, a two-dimensional band of electrons hybridizes with the fermions of a critical holographic sector and a lattice of electrons with Landau quasiparticle structure. We study the transport phenomena like DC resistivity, hall angle, etc. We show that they mimic the strange metal-like behavior for a wide range of temperatures by fine-tuning just one effective dimensionless coupling constant. Furthermore, we find evidence that Planckian dissipation also arises from our effective field theory approach.

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