Flavor Superconductivity from Gauge/Gravity Duality

TL;DR

This paper explores a holographic model of flavor superconductivity within strongly coupled gauge theories, demonstrating a second order phase transition with superconducting features like infinite conductivity and a gap, interpreted as a rho meson superfluid.

Contribution

It provides a detailed holographic realization of flavor superconductivity, including the condensation mechanism, phase transition analysis, and effects of massive flavors within a string theory framework.

Findings

Second order phase transition with critical exponent 1/2.

Superconducting signatures such as infinite dc conductivity and a frequency gap.

Stringy picture of condensation via string recombination.

Abstract

We give a detailed account and extensions of a holographic flavor superconductivity model which we have proposed recently. The model has an explicit field theory realization as strongly coupled N=2 Super Yang-Mills theory with fundamental matter at finite temperature and finite isospin chemical potential. Using gauge/gravity duality, i.e. a probe of two flavor D7-branes in the AdS black hole background, we show that the system undergoes a second order phase transition with critical exponent 1/2. The new ground state may be interpreted as a rho meson superfluid. It shows signatures known from superconductivity, such as an infinite dc conductivity and a gap in the frequency-dependent conductivity. We present a stringy picture of the condensation mechanism in terms of a recombination of strings. We give a detailed account of the evaluation of the non-Abelian Dirac-Born-Infeld action involved using two different methods. Finally we also consider the case of massive flavors and discuss the holographic Meissner-Ochsenfeld effect in our scenario.