Drag force in a strongly coupled anisotropic plasma

TL;DR

This paper investigates the drag force on a heavy quark moving through an anisotropic, strongly coupled plasma using holographic duality, revealing directional dependencies and relativistic behaviors.

Contribution

It provides the first detailed calculation of drag force in an anisotropic plasma via gravity dual, highlighting misalignments and variable drag coefficients.

Findings

Drag coefficient varies with direction and velocity.

Gluon cloud trailing behind quark is misaligned with quark velocity.

In ultra-relativistic limit, drag coefficient scales linearly with momentum.

Abstract

We calculate the drag force experienced by an infinitely massive quark propagating at constant velocity through an anisotropic, strongly coupled N=4 plasma by means of its gravity dual. We find that the gluon cloud trailing behind the quark is generally misaligned with the quark velocity, and that the latter is also misaligned with the force. The drag coefficient $\mu$ can be larger or smaller than the corresponding isotropic value depending on the velocity and the direction of motion. In the ultra-relativistic limit we find that generically $\mu \propto p$. We discuss the conditions under which this behaviour may extend to more general situations.