Comments on Fermi Liquid from Holography

TL;DR

This paper explores Fermi liquid behavior in a strongly coupled supersymmetric gauge theory using holography, revealing a zero sound mode with properties consistent with Landau Fermi liquid theory.

Contribution

It demonstrates the persistence of zero sound mode across different hypermultiplet masses and confirms Fermi liquid characteristics at strong coupling via holographic analysis.

Findings

Zero sound mode exists for all hypermultiplet masses.

The zero sound speed vanishes at the phase transition.

Results align with Landau Fermi liquid theory predictions.

Abstract

We investigate the signatures of Fermi liquid formation in the N=4 super Yang-Mills theory coupled to fundamental hypermultiplet at nonvanishing chemical potential for the global U(1) vector symmetry. At strong 't Hooft coupling the system can be analyzed in terms of the D7 brane dynamics in AdS_5 x S^5 background. The phases with vanishing and finite charge density are separated at zero temperature by a quantum phase transition. In case of vanishing hypermultiplet mass, Karch, Son and Starinets discovered a gapless excitation whose speed equals the speed of sound. We find that this zero sound mode persists to all values of the hypermultiplet mass, and its speed vanishes at the point of phase transition. The value of critical exponent and the ratio of the velocities of zero and first sounds are consistent with the predictions of Landau Fermi liquid theory at strong coupling.