Relativistic BGK hydrodynamics

TL;DR

This paper develops a relativistic hydrodynamics framework using a modified BGK collision kernel, exploring its impact on transport coefficients and proposing a new collision kernel valid at zero chemical potential.

Contribution

It introduces a new collision kernel for relativistic hydrodynamics and analyzes its effects on bulk viscosity, expanding the theoretical tools available for dissipative systems.

Findings

Freedom in choosing matching conditions affects scalar transport.

The new collision kernel is valid at zero chemical potential.

Impact on bulk viscosity coefficients is analyzed.

Abstract

Bhatnagar-Gross-Krook (BGK) collision kernel is employed in the Boltzmann equation to formulate relativistic dissipative hydrodynamics. In this formulation, we find that there remains freedom of choosing a matching condition that affects the scalar transport in the system. We also propose a new collision kernel which, unlike BGK collision kernel, is valid in the limit of zero chemical potential and derive relativistic first-order dissipative hydrodynamics using it. We study the effects of this new formulation on the coefficient of bulk viscosity.