Near Zone Hydrodynamics of AdS/CFT Jet Wakes

TL;DR

This paper investigates the near zone hydrodynamics of a heavy quark jet in strongly-coupled plasma using AdS/CFT, finding that hydrodynamics applies outside a narrow head region close to the jet.

Contribution

It provides a detailed analysis of the jet head region and demonstrates the applicability of Navier-Stokes hydrodynamics beyond this narrow zone in strongly-coupled plasma.

Findings

The head region is confined within a narrow pancake of width ~1/T.

Outside the head, the stress tensor is well described by Navier-Stokes hydrodynamics.

Hydrodynamics accurately models jet-induced stress beyond the head region.

Abstract

The energy-momentum tensor of a supersonic heavy quark jet moving through a strongly-coupled $\mathcal{N}=4$ SYM plasma is analyzed in terms of first-order Navier-Stokes hydrodynamics. We focus on the near zone ``head'' region close to the heavy quark where deviations from hydrodynamic behavior are expected to be large. For realistic quark velocities, $v=0.99$, we find that the non-hydrodynamical head region is confined at a narrow pancake surrounding the jet with a width $\sim 1/T$ and transverse radius $\sim 3/T$. Outside this jet head region, the jet induced stress is well approximated by Navier-Stokes hydrodynamics.