Vanishing DC holographic conductivity from a magnetic monopole condensate

TL;DR

This paper demonstrates that a magnetic monopole condensate in a 4D bulk holographic model causes the DC conductivity of the dual 3D strongly coupled quantum field theory to vanish, revealing a new phase with insulating behavior.

Contribution

It introduces a holographic model with a massive 2-form field that captures magnetic monopole condensation and results in zero DC conductivity in the dual QFT.

Findings

DC conductivity vanishes for any nonzero 2-form mass

AC conductivity's real and imaginary parts are computed

Magnetic monopole condensate induces insulating phase

Abstract

We show how to obtain a vanishing DC conductivity in 3-dimensional strongly coupled QFT's using a massive 2-form field in the bulk that satisfies a special kind of boundary condition. The real and imaginary parts of the AC conductivity are evaluated in this holographic setup and we show that the DC conductivity identically vanishes even for an arbitrarily small (though nonzero) value of the 2-form mass in the bulk. We identify the bulk action of the massive 2-form with an effective theory describing a phase in which magnetic monopoles have condensed in the bulk. Our results indicate that a condensate of magnetic monopoles in a 4-dimensional bulk leads to a vanishing DC holographic conductivity in 3-dimensional strongly coupled QFT's.