Alternating current conductivity and superconducting properties of the holographic effective theory

TL;DR

This paper develops a holographic superconducting model incorporating gauge-axion interactions, revealing complex AC conductivity behaviors and superconducting gaps influenced by momentum dissipation and couplings.

Contribution

It introduces a novel gauge-axion higher derivative term in holographic superconductors, analyzing its effects on AC conductivity and superconducting properties.

Findings

AC conductivity shows non-Drude behavior at weak momentum dissipation.

A low-frequency dip in AC conductivity appears with increased momentum dissipation.

Gauge-axion coupling enhances the superconducting gap at low frequencies.

Abstract

We construct a holographic effective superconducting theory by considering a special gauge-axion higher derivative term. The gauge-axion coupling results in the transport behavior similar to the vortex response in the dual boundary field theory leading to non-Drude behavior of alternating current (AC) conductivity at the weak momentum dissipation. With the momentum dissipation increasing, a dip exhibits in the AC conductivity at low frequency. It is thought to be the result of a combination of the strong momentum dissipation and the gauge-axion coupling. In the superconducting phase, this gauge-axion coupling also plays a key role leading to a more evident gap at the low frequency conductivity. In addition, we also study the combined effects of the strength of momentum dissipation and various couplings among the gauge field, axion fields and the complex scalar field.