On the hydrodynamic attractor of Yang-Mills plasma

TL;DR

This paper identifies and characterizes the hydrodynamic attractor in N=4 supersymmetric Yang-Mills theory's quark-gluon plasma using Borel summation and AdS/CFT simulations, enhancing understanding of far-from-equilibrium hydrodynamics.

Contribution

It determines the hydrodynamic attractor for Bjorken flow in N=4 SYM using Borel summation, providing a precise approximation validated by AdS/CFT simulations.

Findings

The attractor accurately describes far-from-equilibrium dynamics.

Borel summation effectively captures the gradient expansion.

Comparison with AdS/CFT confirms the attractor's validity.

Abstract

There is mounting evidence suggesting that relativistic hydrodynamics becomes relevant for the physics of quark-gluon plasma as the result of nonhydrodynamic modes decaying to an attractor apparent even when the system is far from local equilibrium. Here we determine this attractor for Bjorken flow in N=4 supersymmetric Yang-Mills theory using Borel summation of the gradient expansion of the expectation value of the energy momentum tensor. By comparing the result to numerical simulations of the flow based on the AdS/CFT correspondence we show that it provides an accurate and unambiguous approximation of the hydrodynamic attractor in this system. This development has important implications for the formulation of effective theories of hydrodynamics.