Holographic phonons by gauge-axion coupling

TL;DR

This paper introduces a holographic model with gauge-axion coupling that exhibits spontaneous translational symmetry breaking, leading to viscoelastic behavior and the emergence of phonons and pseudo-phonons, impacting charge transport.

Contribution

It presents a novel holographic model with higher derivative gauge-axion terms that realize phonons and pseudo-phonons, connecting holography with elasticity theory.

Findings

Existence of phonons and pseudo-phonons confirmed

Viscoelastic properties derived from stress tensor analysis

Charge transport influenced by phonon dynamics

Abstract

In this paper, we show that a simple generalization of the holographic axion model can realize spontaneous breaking of translational symmetry by considering a special gauge-axion higher derivative term. The finite real part and imaginary part of the stress tensor imply that the dual boundary system is a viscoelastic solid. By calculating quasi-normal modes and making a comparison with predictions from the elasticity theory, we verify the existence of phonons and pseudo-phonons, where the latter is realized by introducing a weak explicit breaking of translational symmetry, in the transverse channel. Finally, we discuss how the phonon dynamics affects the charge transport.