Transient fluid dynamics with general matching conditions: a first study from the method of moments

TL;DR

This paper derives transient relativistic fluid dynamics from kinetic theory using the method of moments without fixed matching conditions, exploring how these conditions influence the equations and transport coefficients.

Contribution

It introduces a framework for deriving fluid dynamics without specific matching conditions, highlighting their impact on the equations and transport properties.

Findings

Matching conditions significantly affect the equations of motion.

Transport coefficients depend on the choice of matching conditions.

The method provides a flexible approach to relativistic fluid dynamics.

Abstract

Recent works have revealed that matching conditions play a major role on general consistency properties of relativistic fluid dynamics such as causality, stability and wellposedness of the equations of motion. In this paper we derive transient fluid dynamics from kinetic theory, using the method of moments as proposed by Israel and Stewart, without imposing an specific matching condition. We then investigate how the equations of motion and their corresponding transport coefficients are affected by the choice of matching condition.