Flavor Superconductivity & Superfluidity

TL;DR

This paper presents a holographic string theory model of p-wave superconductivity and superfluidity, demonstrating a second order phase transition with characteristic superconducting signatures in a supersymmetric gauge theory context.

Contribution

It introduces a novel D3/D7-brane holographic construction for p-wave superconductors and superfluids, connecting string theory with experimentally relevant superconducting phenomena.

Findings

Demonstrates a second order phase transition with superconducting signatures

Shows a U(1) symmetry breaking and Meissner effect in the model

Provides a string theory picture of pairing mechanisms

Abstract

In these lecture notes we derive a generic holographic string theory realization of a p-wave superconductor and superfluid. For this purpose we also review basic D-brane physics, gauge/gravity methods at finite temperature, key concepts of superconductivity and recent progress in distinct realizations of holographic superconductors and superfluids. Then we focus on a D3/D7-brane construction yielding a superconducting or superfluid vector-condensate. The corresponding gauge theory is 3+1-dimensional N=2 supersymmetric Yang-Mills theory with SU(N) color and SU(2) flavor symmetry. It shows a second order phase transition to a phase in which a U(1) subgroup of the SU(2) symmetry is spontaneously broken and typical superconductivity signatures emerge, such as a conductivity (pseudo-)gap and the Meissner-Ochsenfeld effect. Condensates of this nature are comparable to those recently found experimentally in p-wave superconductors such as a ruthenate compound. A string picture of the pairing mechanism and condensation is given using the exact knowledge of the corresponding field theory degrees of freedom.