Holographic superconductors at zero density

TL;DR

This paper constructs and analyzes zero-density holographic superconductors with analytically known ground states, revealing new IR geometries, phase transition behaviors, and explicit conductivity features, advancing understanding of holographic superconductivity.

Contribution

It introduces a zero-density holographic superconductor model with an analytically available ground state and explores its IR geometries, phase transitions, and conductivity properties.

Findings

Analytic ground state geometry with hyperscaling violation

Numerical finite temperature hairy black hole solutions

Explicit AC conductivity showing superconducting delta and gap

Abstract

We construct holographic superconductors at zero density. The model enjoys a luxury property that the background geometry dual to the ground state is analytically available. It has a hyperscaling-violating geometry in the IR and is asymptotically AdS in the UV. Classification by IR geometries gives new insights on supergravity solutions. We numerically construct the finite temperature solution of hairy black holes and verify the phase transition by tuning a double-trace deformation parameter. For a holographic superconductor from M-theory, we obtain an analytic solution of the AC conductivity, which explicitly shows a superconducting delta function and a hard gap.