Holographic charge localization at brane intersections

TL;DR

This paper uses holographic duality to study how charge localizes at an interface in a strongly coupled system, revealing enhanced conductivity along the interface and effects of broken translation symmetry.

Contribution

It introduces a top-down holographic model with a D3/D5 intersection to analyze charge localization and conductivity near an interface at finite temperature and density.

Findings

Charge localizes around a (1+1)-dimensional defect.

DC conductivity along the interface is significantly enhanced.

Broken translation invariance affects AC and DC conductivities.

Abstract

Using gauge/gravity duality, we investigate charge localization near an interface in a strongly coupled system. For this purpose we consider a top-down holographic model and determine its conductivities. Our model corresponds to a holographic interface which localizes charge around a (1+1)-dimensional defect in a (2+1)-dimensional system. The setup consists of a D3/D5 intersection at finite temperature and charge density. We work in the probe limit, and consider massive embeddings of a D5-brane where the mass depends on one of the field theory spatial directions, with a profile interpolating between a negative and a positive value. We compute the conductivity in the direction parallel and perpendicular to the interface. For the latter case we are able to express the DC conductivity as a function of background horizon data. At the interface, the DC conductivity in the parallel direction is enhanced up to five times with respect to that in the orthogonal one. We study the implications of broken translation invariance for the AC and DC conductivities.