Strongly Coupled Heavy and Light Quark Thermal Motion from AdS/CFT

TL;DR

This paper uses AdS/CFT to analyze the thermal motion of heavy and light quarks in a plasma, calculating diffusion properties and dynamics relevant for understanding quark behavior in heavy ion collisions.

Contribution

It provides a detailed, pedagogical analysis of heavy and light quark motion in a plasma via AdS/CFT, including diffusion coefficients in various dimensions.

Findings

Early-time motion is ballistic, late-time is diffusive.

Diffusion coefficients are derived for both heavy and light quarks.

Results are relevant for relativistic heavy ion phenomenology.

Abstract

We give a pedagogical presentation of heavy and light probe quarks in a thermal plasma using the AdS/CFT correspondence. Three cases are considered: external heavy and light quarks undergoing Brownian motion in the plasma, and an external heavy quark moving through the plasma with a constant velocity. For the first two cases we compute the mean-squared transverse displacement of the string's boundary endpoint. At early times the behaviour is ballistic, while the late time dynamics are diffusive. We extract the diffusion coefficient for both heavy and light quarks in an arbitrary number of dimensions and comment on the relevance for relativistic heavy ion phenomenology.