Holographic metals at finite temperature

TL;DR

This paper presents a holographic model of strongly interacting fermions at finite temperature, revealing a phase transition and finite-temperature transport properties influenced by bulk fermions in a dual gravity setup.

Contribution

It introduces a finite-temperature holographic description of electron clouds over black holes, extending the electron star model and analyzing phase transitions and transport.

Findings

Electron cloud persists at low temperatures, matching electron star results.

A second order phase transition occurs at a critical temperature.

Finite temperature conductivity is influenced by bulk fermions within a finite radial band.

Abstract

A holographic dual description of a 2+1 dimensional system of strongly interacting fermions at low temperature and finite charge density is given in terms of an electron cloud suspended over the horizon of a charged black hole in asymptotically AdS spacetime. The electron star of Hartnoll and Tavanfar is recovered in the limit of zero temperature, while at higher temperatures the fraction of charge carried by the electron cloud is reduced and at a critical temperature there is a second order phase transition to a configuration with only a charged black hole. The geometric structure implies that finite temperature transport coefficients, including the AC electrical conductivity, only receive contributions from bulk fermions within a finite band in the radial direction.