Hot Spacetimes for Cold Atoms

TL;DR

This work constructs explicit string-theoretic duals for non-relativistic conformal field theories at finite temperature and density by generating Schrödinger-invariant backgrounds via the Null Melvin Twist. The authors embed Sch^{2}_{5} geometries into Type IIB string theory, realize finite-T and finite-μ NRCFTs, and analyze their thermodynamics and transport, showing that η/s = 1/(4π) holds in these non-relativistic holographic models. They elucidate the role of the DLCQ_β construction in defining the dual NRCFT and derive density, energy, and pressure relations consistent with scale invariance for z = d = 2, including a zero-density limit and a finite-density fixed point. The results establish a holographic framework for strongly coupled cold-atom systems, offering a controlled setting to study universal features such as the KSS bound and finite-density dynamics in non-relativistic theories.

Abstract

Building on our earlier work and that of Son, we construct string theory duals of non-relativistic critical phenomena at finite temperature and density. Concretely, we find black hole solutions of type IIB supergravity whose asymptotic geometries realize the Schroedinger group as isometries. We then identify the non-relativistic conformal field theories to which they are dual. We analyze the thermodynamics of these black holes, which turn out to describe the system at finite temperature and finite density. The strong-coupling result for the shear viscosity of the dual non-relativistic field theory saturates the KSS bound.