Well-posedness of anisotropic and homogeneous solutions to the Einstein-Boltzmann system with a conformal-gauge singularity

Fuente: arXiv
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Hauptverfasser: Lee, Ho, Nungesser, Ernesto, Stalker, John, Tod, Paul
Format: Preprint
Veröffentlicht: 2023
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author Lee, Ho
Nungesser, Ernesto
Stalker, John
Tod, Paul
author_facet Lee, Ho
Nungesser, Ernesto
Stalker, John
Tod, Paul
contents We consider the Einstein-Boltzmann system for massless particles in the Bianchi I space-time with scattering cross-sections in a certain range of soft potentials. We assume that the space-time has an initial conformal gauge singularity and show that the initial value problem is well posed with data given at the singularity. This is understood by considering conformally rescaled equations. The Einstein equations become a system of singular ordinary differential equations, for which we establish an existence theorem which requires several differentiability and eigenvalue conditions on the coefficient functions together with the Fuchsian conditions. The Boltzmann equation is regularized by a suitable choice of time coordinate, but still has singularities in momentum variables. This is resolved by considering singular weights, and the existence is obtained by exploiting singular moment estimates.
format Preprint
id arxiv_https___arxiv_org_abs_2305_15902
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Well-posedness of anisotropic and homogeneous solutions to the Einstein-Boltzmann system with a conformal-gauge singularity
Lee, Ho
Nungesser, Ernesto
Stalker, John
Tod, Paul
General Relativity and Quantum Cosmology
Mathematical Physics
We consider the Einstein-Boltzmann system for massless particles in the Bianchi I space-time with scattering cross-sections in a certain range of soft potentials. We assume that the space-time has an initial conformal gauge singularity and show that the initial value problem is well posed with data given at the singularity. This is understood by considering conformally rescaled equations. The Einstein equations become a system of singular ordinary differential equations, for which we establish an existence theorem which requires several differentiability and eigenvalue conditions on the coefficient functions together with the Fuchsian conditions. The Boltzmann equation is regularized by a suitable choice of time coordinate, but still has singularities in momentum variables. This is resolved by considering singular weights, and the existence is obtained by exploiting singular moment estimates.
title Well-posedness of anisotropic and homogeneous solutions to the Einstein-Boltzmann system with a conformal-gauge singularity
topic General Relativity and Quantum Cosmology
Mathematical Physics
url https://arxiv.org/abs/2305.15902