Towards strange metallic holography

TL;DR

This paper develops a holographic model for strange metallic behavior, capturing non-Fermi liquid scalings like linear resistivity by coupling quantum critical theories to probe charge carriers, and explores string theory realizations of Lifshitz geometries.

Contribution

It introduces a holographic framework for strange metals using Lifshitz-invariant theories coupled to probe charges, with new string theory realizations and analysis of RG flow features.

Findings

Demonstrates anomalous temperature and frequency scalings of conductivity.

Matches non-Fermi liquid scalings such as linear resistivity.

Identifies three string theory realizations of Lifshitz geometries.

Abstract

We initiate a holographic model building approach to `strange metallic' phenomenology. Our model couples a neutral Lifshitz-invariant quantum critical theory, dual to a bulk gravitational background, to a finite density of gapped probe charge carriers, dually described by D-branes. In the physical regime of temperature much lower than the charge density and gap, we exhibit anomalous scalings of the temperature and frequency dependent conductivity. Choosing the dynamical critical exponent $z$ appropriately we can match the non-Fermi liquid scalings, such as linear resistivity, observed in strange metal regimes. As part of our investigation we outline three distinct string theory realizations of Lifshitz geometries: from F theory, from polarised branes, and from a gravitating charged Fermi gas. We also identify general features of renormalisation group flow in Lifshitz theories, such as the appearance of relevant charge-charge interactions when $z \geq 2$. We outline a program to extend this model building approach to other anomalous observables of interest such as the Hall conductivity.