Light-Cone Reduction vs. TsT transformations : A Fluid Dynamics Perspective

TL;DR

This paper compares two holographic methods—light-cone reduction and TsT transformations—for deriving the constitutive relations and transport coefficients of a charged Schrödinger fluid in 2+1 dimensions, showing they produce equivalent results within a restricted thermodynamic class.

Contribution

It demonstrates the equivalence of holographic light-cone reduction and TsT transformation approaches in deriving charged Schrödinger fluid properties.

Findings

Both methods yield the same effective fluid system.

The holographic approach confirms the restricted thermodynamics of the light-cone reduced fluid.

First order transport coefficients are explicitly computed.

Abstract

We compute constitutive relations for a charged $(2+1)$ dimensional Schr\"odinger fluid up to first order in derivative expansion, using holographic techniques. Starting with a locally boosted, asymptotically $AdS$, $4+1$ dimensional charged black brane geometry, we uplift that to ten dimensions and perform $TsT$ transformations to obtain an effective five dimensional local black brane solution with asymptotically Schr\"odinger isometries. By suitably implementing the holographic techniques, we compute the constitutive relations for the effective fluid living on the boundary of this space-time and extract first order transport coefficients from these relations. Schr\"odinger fluid can also be obtained by reducing a charged relativistic conformal fluid over light-cone. It turns out that both the approaches result the same system at the end. Fluid obtained by light-cone reduction satisfies a restricted class of thermodynamics. Here, we see that the charged fluid obtained holographically also belongs to the same restricted class.