Superconductivity from gauge/gravity duality with flavor

TL;DR

This paper uses gauge/gravity duality to study a strongly-coupled supersymmetric gauge theory with fundamental matter, revealing a second order phase transition with superconductivity-like features at finite isospin chemical potential.

Contribution

It provides a holographic model demonstrating a superconductivity-like phase transition in N=2 SYM theory with fundamental matter, including explicit dual string descriptions.

Findings

Identifies a critical temperature for a second order phase transition.

Shows spontaneous symmetry breaking with a flavor current acquiring a vev.

Demonstrates superconductivity signatures like infinite dc conductivity and a frequency gap.

Abstract

We consider thermal strongly-coupled N=2 SYM theory with fundamental matter at finite isospin chemical potential. Using gauge/gravity duality, i.e. a probe of two flavor D7-branes embedded in the AdS black hole background, we find a critical temperature at which the system undergoes a second order phase transition. The critical exponent of this transition is one half and coincides with the result from mean field theory. In the thermodynamically favored phase, a flavor current acquires a vev and breaks an Abelian symmetry spontaneously. This new phase shows signatures known from superconductivity, such as an infinite dc conductivity and a gap in the frequency-dependent conductivity. The gravity setup allows for an explicit identification of the degrees of freedom in the dual field theory, as well as for a dual string picture of the condensation process.