Dissipation in Holographic Superfluids

TL;DR

This paper investigates dissipation mechanisms in holographic superfluids at finite temperature, deriving constitutive relations and transport coefficients, analyzing behavior near phase transitions, and studying pseudo-Goldstone modes with symmetry breaking.

Contribution

It provides analytic expressions for dissipative transport coefficients and explores the breakdown of hydrodynamics near phase transitions in holographic superfluids.

Findings

Transport coefficients expressed in terms of thermodynamics and horizon data

Explicit demonstration of hydrodynamic breakdown near phase transition

Characterization of pseudo-Goldstone mode frequency and decay rate

Abstract

We study dissipation in holographic superfluids at finite temperature and zero chemical potential. The zero overlap with the heat current allows us to isolate the physics of the conserved current corresponding to the broken global $U(1)$. By using analytic techniques we write constitutive relations including the first non-trivial dissipative terms. The corresponding transport coefficients are determined in terms of thermodynamic quantities and the black hole horizon data. By analysing their behaviour close to the phase transition we show explicitly the breakdown of the hydrodynamic expansion. Finally, we study the pseudo-Goldstone mode that emerges upon introducing a perturbative symmetry breaking source and we determine its resonant frequency and decay rate.