Solutions of Friedmann's Equations and Cosmological Consequences

Fuente: arXiv
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Autore principale: Yang, Yisong
Natura: Preprint
Pubblicazione: 2024
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author Yang, Yisong
author_facet Yang, Yisong
contents The Einstein equations of general relativity reduce, when the spacetime metric is of the Friedmann--Lemaitre--Robertson--Walker type governing an isotropic and homogeneous universe, to the Friedmann equations, which is a set of nonlinear ordinary differential equations, determining the law of evolution of the spatial scale factor, in terms of the Hubble ``constant''. It is a challenging task, not always possible, to solve these equations. In this talk, we present some insights from solving and analyzing the Friedmann equations and their implications to evolutionary cosmology. In particular, in the Chaplygin fluid universe, we derive a universal formula for the asymptotic exponential growth rate of the scale factor which indicates that, as far as there is a tiny presence of nonlinear (exotic) matter, linear (conventional) matter makes contribution to the dark energy, which becomes significant near the phantom divide line. Joint work with Shouxin Chen, Gary W. Gibbons, and Yijun Li.
format Preprint
id arxiv_https___arxiv_org_abs_2407_19250
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Solutions of Friedmann's Equations and Cosmological Consequences
Yang, Yisong
General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
Mathematical Physics
83C15, 83F05
The Einstein equations of general relativity reduce, when the spacetime metric is of the Friedmann--Lemaitre--Robertson--Walker type governing an isotropic and homogeneous universe, to the Friedmann equations, which is a set of nonlinear ordinary differential equations, determining the law of evolution of the spatial scale factor, in terms of the Hubble ``constant''. It is a challenging task, not always possible, to solve these equations. In this talk, we present some insights from solving and analyzing the Friedmann equations and their implications to evolutionary cosmology. In particular, in the Chaplygin fluid universe, we derive a universal formula for the asymptotic exponential growth rate of the scale factor which indicates that, as far as there is a tiny presence of nonlinear (exotic) matter, linear (conventional) matter makes contribution to the dark energy, which becomes significant near the phantom divide line. Joint work with Shouxin Chen, Gary W. Gibbons, and Yijun Li.
title Solutions of Friedmann's Equations and Cosmological Consequences
topic General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
Mathematical Physics
83C15, 83F05
url https://arxiv.org/abs/2407.19250