Holographic Quantum Critical Transport without Self-Duality

TL;DR

This paper investigates the frequency-dependent charge transport near quantum critical points in 2+1 dimensions using holography, analyzing how higher-derivative corrections affect conductivity beyond the self-dual Einstein-Maxwell model.

Contribution

It introduces a framework for understanding non-trivial frequency dependence of conductivity by including higher-derivative corrections in holographic models, extending beyond the self-dual Einstein-Maxwell theory.

Findings

Higher-derivative terms limit the frequency dependence of conductivity.

Physical consistency constrains the form of higher-derivative corrections.

The frequency dependence can be interpreted via particle-like or vortex-like excitations.

Abstract

We describe general features of frequency-dependent charge transport near strongly interacting quantum critical points in 2+1 dimensions. The simplest description using the AdS/CFT correspondence leads to a self-dual Einstein-Maxwell theory on AdS_4, which fixes the conductivity at a frequency-independent self-dual value. We describe the general structure of higher-derivative corrections to the Einstein-Maxwell theory, and compute their implications for the frequency dependence of the quantum-critical conductivity. We show that physical consistency conditions on the higher-derivative terms allow only a limited frequency dependence in the conductivity. The frequency dependence is amenable to a physical interpretation using transport of either particle-like or vortex-like excitations.