Holographic Bjorken Flow at Large-D

TL;DR

This paper investigates the dynamics of strongly coupled gauge theories undergoing boost invariant expansion using gauge/gravity duality, focusing on the large-D limit and its implications for hydrodynamics and non-hydrodynamic modes.

Contribution

It explores the large-D limit of holographic Bjorken flow, constrains transport coefficients, and analyzes non-hydrodynamic modes via a trans-series expansion.

Findings

Large-D dynamics are governed by hydrodynamics.

Constraints on transport coefficients up to 6th order in gradients.

Non-hydrodynamic modes appear as a trans-series in D.

Abstract

We use gauge/gravity duality to study the dynamics of strongly coupled gauge theories undergoing boost invariant expansion in an arbitrary number of space-time dimensions (D). By keeping the scale of the late-time energy density fixed, we explore the infinite-D limit and study the first few corrections to this expansion. In agreement with other studies, we find that the large-D dynamics are controlled by hydrodynamics and we use our computation to constrain the leading large-D dependence of a certain combination of transport coefficients up to 6-th order in gradients. Going beyond late time physics, we discuss how non-hydrodynamic modes appear in the large-D expansion in the form of a trans-series in D, identical to the non-perturbative contributions to the gradient expansion. We discuss the consequence of this trans-series in the non-convergence of the large-D expansion.