Cosmological solutions of the Vlasov-Einstein system with spherical, plane, and hyperbolic symmetry

TL;DR

This paper studies the evolution of a collisionless gas in cosmological models with different symmetries, proving solutions exist up to a singularity under small initial conditions.

Contribution

It establishes local existence and continuation criteria for solutions of the Vlasov-Einstein system with spherical, plane, and hyperbolic symmetry in a cosmological context.

Findings

Solutions exist up to a curvature and crushing singularity for small initial data.

A continuation criterion based on boundedness of momenta is proven.

The analysis applies to various symmetric cosmological models.

Abstract

The Vlasov-Einstein system describes a self-gravitating, collisionless gas within the framework of general relativity. We investigate the initial value problem in a cosmological setting with spherical, plane, or hyperbolic symmetry and prove that for small initial data solutions exist up to a spacetime singularity which is a curvature and a crushing singularity. An important tool in the analysis is a local existence result with a continuation criterion saying that solutions can be extended as long as the momenta in the support of the phase-space distribution of the matter remain bounded.