Holographic Flavor Transport in Schroedinger Spacetime

TL;DR

This paper investigates the transport properties of charge carriers in a non-relativistic strongly-coupled quantum field theory using gauge-gravity duality, revealing relativistic and non-relativistic scaling behaviors in different energy regimes.

Contribution

It introduces a holographic model with Schroedinger symmetry to analyze flavor transport, highlighting the impact of irrelevant deformations on conductivity scaling.

Findings

Infrared conductivity shows relativistic scaling with temperature or frequency.

Ultraviolet conductivity exhibits non-relativistic scaling with dynamical exponent z=2.

The model captures the transition between relativistic and non-relativistic regimes.

Abstract

We use gauge-gravity duality to study the transport properties of a finite density of charge carriers in a strongly-coupled theory with non-relativistic symmetry. The field theory is N=4 supersymmetric SU(Nc) Yang-Mills theory in the limit of large Nc and with large 't Hooft coupling, deformed by an irrelevant operator, coupled to a number Nf of massive N=2 supersymmetric hypermultiplets in the fundamental representation of the gauge group, i.e. flavor fields. The irrelevant deformation breaks the relativistic conformal group down to the Schroedinger group, which has non-relativistic scale invariance with dynamical exponent z=2. Introducing a finite baryon number density of the flavor fields provides us with charge carriers. We compute the associated DC and AC conductivities using the dual gravitational description of probe D7-branes in an asymptotically Schroedinger spacetime. We generically find that in the infrared the conductivity exhibits scaling with temperature or frequency that is relativistic, while in the ultraviolet the scalings appear to be non-relativistic with dynamical exponent z=2, as expected in the presence of the irrelevant deformation.