Viscosity spectral function of a scale invariant non-relativistic fluid from holography

TL;DR

This paper investigates the viscosity spectral function of a holographic non-relativistic fluid with Schrödinger symmetry, revealing unique high-frequency behavior, negative relaxation time, and an asymmetric quasi-normal mode spectrum.

Contribution

It provides the first numerical and analytical analysis of the viscosity spectral function in a Schrödinger-symmetric holographic fluid, uncovering novel spectral properties.

Findings

High frequency behavior follows a fractional 1/3 power law.

Viscous relaxation time is negative.

Quasi-normal mode spectrum is not doubled in the shear channel.

Abstract

We study the viscosity spectral function of a holographic 2+1 dimensional fluid with Schroedinger symmetry. The model is based on a twisted compactification of $Ads_5\times S_5$. We numerically compute the spectral function of the stress tensor correlator for all frequencies, and analytically study the limits of high and low frequency. We compute the shear viscosity, the viscous relaxation time, and the quasi-normal mode spectrum in the shear channel. We find a number of unexpected results: The high frequency behavior is governed by a fractional 1/3 power law, the viscous relaxation time is negative, and the quasi-normal mode spectrum in the shear channel is not doubled.