The stress-energy tensor of a quark moving through a strongly-coupled N=4 supersymmetric Yang-Mills plasma: comparing hydrodynamics and AdS/CFT

TL;DR

This paper compares the stress-energy tensor of a moving quark in a strongly-coupled plasma, calculated via AdS/CFT, with hydrodynamic predictions, showing remarkable agreement even at short distances.

Contribution

It demonstrates that hydrodynamics accurately reproduces the quark's wake in the plasma at surprisingly short distances, using a simplified gravitational analysis.

Findings

Hydrodynamics matches the full AdS/CFT result within 2/T of the quark.

A simplified formulation of Einstein equations is effective for this analysis.

The method can be extended to other bulk sources.

Abstract

The stress-energy tensor of a quark moving through a strongly coupled N=4 supersymmetric Yang-Mills plasma is evaluated using gauge/string duality. The accuracy with which the resulting wake, in position space, is reproduced by hydrodynamics is examined. Remarkable agreement is found between hydrodynamics and the complete result down to distances less than 2/T away from the quark. In performing the gravitational analysis, we use a relatively simple formulation of the bulk to boundary problem in which the linearized Einstein field equations are fully decoupled. Our analysis easily generalizes to other sources in the bulk.