Hard-gapped Holographic Superconductors

TL;DR

This paper constructs a zero-temperature holographic p-wave superconductor model with a hard gap, revealing unique IR conformal symmetry and zero conductivity below the gap, contrasting with scalar models.

Contribution

It introduces a zero-temperature solution for a p-wave holographic superconductor with a hard gap and emergent IR conformal symmetry, differing from scalar-based models.

Findings

Zero temperature solution is a smooth soliton with zero horizon size.

The system exhibits a hard gap in gauge field fluctuations.

Real part of conductivity is zero below the gap frequency.

Abstract

In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.