The near equilibrium Einstein-Boltzmann system with a simplified collision term
General Relativity and Quantum Cosmology
2026-04-13 v1
Abstract
A simplified relativistic kinetic theory for gases with internal degrees of freedom, based on a BGK-type collision term, is considered. First the Boltzmann equation is rewritten in tetrad form and then thermal coefficients are determined to first order in the Chapman-Enskog expansion for general spacetimes. The results are used to construct a self-consistent system of first order differential equations, equivalent to the Einstein-Boltzmann system, for some spatially homogeneous models with viscosity and heat flow.
Cite
@article{arxiv.2604.09262,
title = {The near equilibrium Einstein-Boltzmann system with a simplified collision term},
author = {Philip Semrén and Michael Bradley and João M. S. Oliveira and M. Piedade Machado Ramos},
journal= {arXiv preprint arXiv:2604.09262},
year = {2026}
}
Comments
34 pages, 4 figures