No Line on the Horizon: On Uniform Acceleration and Gluonic Fields at Strong Coupling

TL;DR

This paper investigates the behavior of strings in AdS spacetime related to strongly-coupled conformal field theories, revealing new insights into string embeddings, gluonic shock waves, and the interpretation of worldsheet horizons for accelerated quarks.

Contribution

It identifies the correct continuation of string embeddings for uniformly accelerated quarks and clarifies the role of the worldsheet horizon in the dual description of gluonic fields.

Findings

Corrected the unphysical termination of string embeddings at the worldsheet horizon.

Discovered that the worldsheet horizon does not always separate quark and radiation regions.

Showed that gluonic shock waves are encoded in the string continuation for accelerated quarks.

Abstract

We study a few assorted questions about the behavior of strings on anti-de Sitter spacetime (AdS), or equivalently, `flux tubes' in strongly-coupled conformal field theories (CFTs). For the case where the `flux tube' is sourced by a uniformly accelerated quark (or, more generally, a quark that asymptotes to uniform acceleration in the remote past), we point out that the dual string embedding known heretofore terminates unphysically at the worldsheet horizon, and identify the correct continuation, which is found to encode a gluonic shock wave. For arbitrary quark motion, we show that, contrary to common understanding, the worldsheet horizon does not in general represent a dividing line between the portions of the string respectively dual to the quark and to the gluonic radiation emitted by it.