Noisy Branes

TL;DR

This paper investigates how disorder affects strongly coupled 2+1 dimensional matter, revealing that weak disorder can enhance conductivity at low charge densities and induce sublinear behavior similar to graphene.

Contribution

It provides analytic and numerical analysis of disorder effects on charge density, condensate, and conductivity in a holographic D3/D5 system, including a novel sublinear conductivity behavior.

Findings

Disorder enhances DC conductivity at low charge density.

Disorder reduces conductivity at high charge density.

Disorder induces sublinear conductivity dependence on charge density.

Abstract

We study the effects of disorder on strongly coupled compressible matter in 2+1 dimensions. Our system consists of a D3/D5 intersection at finite temperature and in the presence of a disordered chemical potential. We first study the impact of disorder on the charge density and the quark condensate. Next, we focus on the DC conductivity and derive analytic expressions for the corrections induced by weak disorder. It is found that disorder enhances the DC conductivity at low charge density, while for large charge density the conductivity is reduced. We present numerical simulations both for weak and strong disorder. Finally, we show how disorder gives rise to a sublinear behavior for the conductivity as a function of the charge density, a behavior qualitatively similar to predictions and observations for electric transport in graphene.