Fermi surfaces in maximal gauged supergravity

TL;DR

This paper investigates fermion fluctuations in extremal charged black hole backgrounds within maximal gauged supergravity, revealing non-Fermi liquid behavior and Fermi surface singularities in dual conformal field theories at finite chemical potential.

Contribution

It provides the first analysis of fermion fluctuation equations in these supergravity backgrounds, identifying Fermi surface singularities and non-Fermi liquid behavior in dual theories.

Findings

Fermi surface singularities observed in dual CFTs at finite chemical potential.

Non-Fermi liquid behavior with scaling exponents less than one-half.

In five dimensions, Fermi momentum and exponents are simple, with gauginos possibly carrying most of the black hole charge.

Abstract

We obtain fermion fluctuation equations around extremal charged black hole geometries in maximal gauged supergravity in four and five dimensions, and we demonstrate that their solutions display Fermi surface singularities for the dual conformal field theories at finite chemical potential. The four-dimensional case is a massless charged fermion, while in five dimensions we find a massive charged fermion with a Pauli coupling. In both cases, the corresponding scaling exponent is less than one half, leading to non-Fermi liquid behavior with no stable quasiparticles, although some excitations have widths more than ten times smaller than their excitation energy. In the five-dimensional case, both the Fermi momentum and the scaling exponent appear to have simple values, and a Luttinger calculation suggests that the gauginos may carry most of the charge of the black hole.