Shock Treatment: Heavy Quark Drag in a Novel AdS Geometry

TL;DR

This paper extends the AdS/CFT heavy quark drag calculations to shock wave geometries, allowing analysis of both hot and cold nuclear matter with a simplified analytic approach.

Contribution

It introduces a new analytic method for calculating heavy quark drag in shock wave backgrounds, generalizing previous thermal medium results to arbitrary matter distributions.

Findings

Derived a simplified analytic expression for the drag force in shock geometries.

Showed the drag coefficient reduces to known thermal results when the shock is thermalized.

Extended the applicability of heavy quark drag calculations to non-thermalized media.

Abstract

We calculate the drag force on a heavy quark hit by a shock wave, thus generalizing the strongly coupled AdS/CFT heavy quark drag calculations to both hot and cold nuclear matter. The derivation employs the trailing string configuration, similar to that used in the literature for a quark moving through a thermal medium, though in the shock metric the string profile is described by a much simpler analytic function. Our expression for the drag depends on the typical transverse momentum scale of the matter in the shock. For a thermal medium this scale becomes proportional to the temperature, making our drag coefficient and momentum limit of applicability identical to those found previously. As the shock wave can be composed of either thermalized or non-thermalized media, our derivation extends the existing drag calculations to the case of arbitrarily distributed matter.