Shear viscosity of boost invariant plasma at finite coupling

TL;DR

This paper investigates how finite coupling effects in string theory alter the shear viscosity of an expanding plasma, revealing discrepancies with equilibrium calculations and highlighting complexities in dual descriptions.

Contribution

It provides the first computation of finite 't Hooft coupling corrections to shear viscosity in a boost invariant plasma using string theory alpha' corrections.

Findings

Finite coupling corrections reduce shear viscosity compared to infinite coupling limit.

Discrepancy observed between real-time and equilibrium correlation function results.

Highlights potential issues in the dual description of expanding plasmas.

Abstract

We discuss string theory alpha' corrections in the dual description of the expanding boost invariant N=4 supersymmetric Yang-Mills plasma at strong coupling. We compute finite 't Hooft coupling corrections to the shear viscosity and find that it disagrees with the equilibrium correlation function computations. We comment on the possible source of the discrepancy.