The Stability of Relativistic Fluids in Linearly Expanding Cosmologies

Fuente: arXiv
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Auteurs principaux: Fajman, David, Ofner, Maximilian, Oliynyk, Todd A., Wyatt, Zoe
Format: Preprint
Publié: 2023
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author Fajman, David
Ofner, Maximilian
Oliynyk, Todd A.
Wyatt, Zoe
author_facet Fajman, David
Ofner, Maximilian
Oliynyk, Todd A.
Wyatt, Zoe
contents In this paper we study cosmological solutions to the Einstein--Euler equations. We first establish the future stability of nonlinear perturbations of a class of homogeneous solutions to the relativistic Euler equations on fixed linearly expanding cosmological spacetimes with a linear equation of state $p=K ρ$ for the parameter values $K \in (0,1/3)$. This removes the restriction to irrotational perturbations in earlier work, and relies on a novel transformation of the fluid variables that is well-adapted to Fuchsian methods. We then apply this new transformation to show the global regularity and stability of the Milne spacetime under the coupled Einstein--Euler equations, again with a linear equation of state $p=K ρ$, $K \in (0,1/3)$. Our proof requires a correction mechanism to account for the spatially curved geometry. In total, this is indicative that structure formation in cosmological fluid-filled spacetimes requires an epoch of decelerated expansion.
format Preprint
id arxiv_https___arxiv_org_abs_2301_11191
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle The Stability of Relativistic Fluids in Linearly Expanding Cosmologies
Fajman, David
Ofner, Maximilian
Oliynyk, Todd A.
Wyatt, Zoe
Analysis of PDEs
General Relativity and Quantum Cosmology
35Q75, 35Q31, 83C05, 83F05
In this paper we study cosmological solutions to the Einstein--Euler equations. We first establish the future stability of nonlinear perturbations of a class of homogeneous solutions to the relativistic Euler equations on fixed linearly expanding cosmological spacetimes with a linear equation of state $p=K ρ$ for the parameter values $K \in (0,1/3)$. This removes the restriction to irrotational perturbations in earlier work, and relies on a novel transformation of the fluid variables that is well-adapted to Fuchsian methods. We then apply this new transformation to show the global regularity and stability of the Milne spacetime under the coupled Einstein--Euler equations, again with a linear equation of state $p=K ρ$, $K \in (0,1/3)$. Our proof requires a correction mechanism to account for the spatially curved geometry. In total, this is indicative that structure formation in cosmological fluid-filled spacetimes requires an epoch of decelerated expansion.
title The Stability of Relativistic Fluids in Linearly Expanding Cosmologies
topic Analysis of PDEs
General Relativity and Quantum Cosmology
35Q75, 35Q31, 83C05, 83F05
url https://arxiv.org/abs/2301.11191