Non-equilibrium dynamics in Holography

TL;DR

This paper explores non-equilibrium phenomena in strongly coupled field theories using holography, covering topics from hydrodynamics with anomalies and momentum dissipation to quantum gravity in de-Sitter space and $T\bar T$ deformations, revealing new insights and bounds.

Contribution

It introduces a hydrodynamic framework for anomalous theories with external fields, revises hydrodynamics for broken translational invariance, and derives entanglement entropies for $T\bar T$ deformations within holography.

Findings

Transport coefficients due to chiral anomaly identified

Revised thermodynamic coefficients for broken translational invariance

Derived entanglement entropies for $T\bar T$ deformations

Abstract

We investigate aspects of non-equilibrium dynamics of strongly coupled field theories within holography. We establish a hydrodynamic description for anomalous quantum field theories subject to a strong external field for the first time in the literature. Within holography, we explicitly demonstrate which transport coefficients are non-zero due to the chiral anomaly and thus important for the transport. We show that the standard treatment of the hydrodynamics for spontaneously broken translational invariance is more subtle and has to be revised since the description is missing a novel thermodynamic coefficient. Within holographic massive gravity, we lay out a road map for extensions of hydrodynamics to momentum dissipation. Furthermore, we study the imprint of spontaneously broken translations beyond linear response theory in terms of periodically driven strongly coupled quantum field theories. Another important non-equilibrium scenario specially important for the understanding of our universe is quantum gravity in de-Sitter. Recently, the bold claim of the so-called swampland conjectures has attracted great interest since it banishes all stable theories of quantum gravity on de-Sitter with matter into swampland. Within the well-defined framework of the DS/dS correspondence, we set out to derive consistency conditions on the matter content in de-Sitter. Surprisingly, our proposed bound is violated by any reasonable form of matter. In our discussion, we find a novel one-parameter family of entangling surfaces. The last chapter is dedicated to solvable irrelevant deformations in quantum field theory -- the $T\bar T$ deformation. Within holography, we derive the entanglement entropies for generic subintervals on a sphere. We also resolve the confusion in the literature about a seeming mismatch between the holographic field theory results for the entanglement entropy in general dimensions.