Quasinormal modes of magnetic and electric black branes versus far from equilibrium anisotropic fluids

TL;DR

This paper investigates the late-time approach to equilibrium in strongly coupled 3+1 dimensional systems with charge density or magnetic fields using gauge/gravity duality, focusing on quasinormal modes of black branes.

Contribution

It computes specific quasinormal modes for charged and magnetic black branes, providing benchmarks for holographic thermalization studies.

Findings

Computed tensor and vector quasinormal modes of Reissner-Nordström black branes.

Calculated scalar and tensor quasinormal modes of magnetic black branes.

Identified modes related to late-time relaxation after initial pressure anisotropy.

Abstract

Detailed knowledge about equilibration processes is of interest for various fields of physics, including heavy ion collision experiments and quantum quenched condensed matter systems. We study the approach to equilibrium at late times within two types of strongly coupled thermal systems in 3+1 dimensions: systems in the presence of (i) a non-zero charge density, or (ii) a magnetic field at vanishing charge density. Utilizing the gauge/gravity correspondence, we map the aforementioned problem to the computation of quasinormal frequencies around two particular classes of black branes within the Einstein-Maxwell theory. We compute (i) the tensor and vector quasinormal modes of Reissner-Nordstr\"om black branes and (ii) the scalar, as well as tensor quasinormal modes of magnetic black branes. Some of these quasinormal modes correspond to the late-time relaxation of the above systems after starting with initial pressure anisotropy. We provide benchmarks which need to be matched at late-times by all holographic thermalization codes with the appropriate symmetries.