Quantum Fluctuations and the Unruh Effect in Strongly-Coupled Conformal Field Theories

TL;DR

This paper uses AdS/CFT to analyze quantum fluctuations of an accelerated quark in strongly-coupled conformal field theories, revealing connections between radiation, the Unruh effect, and thermal media.

Contribution

It provides a detailed comparison of quantum fluctuations from radiation and Unruh thermal effects, and explores the impact of conformal transformations on the boundary and bulk descriptions.

Findings

Quantum fluctuations are linked to gluonic radiation and Unruh thermal effects.

Conformal transformation removes the acceleration horizon from the boundary theory.

Calculated the stress-energy tensor of the Unruh thermal medium.

Abstract

Through the AdS/CFT correspondence, we study a uniformly accelerated quark in the vacuum of strongly-coupled conformal field theories in various dimensions, and determine the resulting stochastic fluctuations of the quark trajectory. From the perspective of an inertial observer, these are quantum fluctuations induced by the gluonic radiation emitted by the accelerated quark. From the point of view of the quark itself, they originate from the thermal medium predicted by the Unruh effect. We scrutinize the relation between these two descriptions in the gravity side of the correspondence, and show in particular that upon transforming the conformal field theory from Rindler space to the open Einstein universe, the acceleration horizon disappears from the boundary theory but is preserved in the bulk. This transformation allows us to directly connect our calculation of radiation-induced fluctuations in vacuum with the analysis by de Boer et al. of the Brownian motion of a quark that is on average static within a thermal medium. Combining this same bulk transformation with previous results of Emparan, we are also able to compute the stress-energy tensor of the Unruh thermal medium.