Extraction of shear viscosity in stationary states of relativistic particle systems

TL;DR

This paper develops a microscopic method to extract shear viscosity in relativistic particle systems, validating it against known analytic and pQCD-based results for elastic and inelastic scatterings.

Contribution

It introduces a novel microscopic approach to determine shear viscosity in relativistic systems using a particle cascade and Navier-Stokes ansatz, confirming its accuracy.

Findings

Excellent agreement with analytic shear viscosity values for elastic scatterings.

Consistent shear viscosity results for gluonic systems with pQCD cross sections.

Method applicable to both elastic and inelastic scattering scenarios.

Abstract

Starting from a classical picture of shear viscosity we construct a stationary velocity gradient in a microscopic parton cascade. Employing the Navier-Stokes ansatz we extract the shear viscosity coefficient $\eta$. For elastic isotropic scatterings we find an excellent agreement with the analytic values. This confirms the applicability of this method. Furthermore for both elastic and inelastic scatterings with pQCD based cross sections we extract the shear viscosity coefficient $\eta$ for a pure gluonic system and find a good agreement with already published calculations.