Analytic solutions for the Bianchi I universe coupled to several barotropic perfect fluids

We consider the Bianchi I geometry coupled to several species of comoving barotropic perfect fluids with a linear equation of state in the context of general relativity. The solution of the dynamics can be reduced to a quadrature, which can be explicitly performed in certain cases. In particular, we...

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Bibliographic Details
Published in:arXiv.org 2024-10
Main Authors: Brizuela, David, Uria, Sara F
Format: Article
Language:English
Subjects:
Equations of state
Exact solutions
Linear equations
Quadratures
Relativity
Singularity (mathematics)
Online Access:Get full text
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Summary:We consider the Bianchi I geometry coupled to several species of comoving barotropic perfect fluids with a linear equation of state in the context of general relativity. The solution of the dynamics can be reduced to a quadrature, which can be explicitly performed in certain cases. In particular, we obtain the explicit solution for one species, as well as for two species, given their barotropic indices obey a certain relation. These solutions include and generalize different models studied in the literature. For completeness, we analyze all the different possible signs of the matter energy densities, and we obtain a particularly interesting model in which an exotic species produces a bounce of the scale factor, providing a singularity-free cosmology, and then decays to leave a nonexotic component as the dominant fluid for large volumes.
ISSN:2331-8422
DOI:10.48550/arxiv.2406.20070