1. Viscous universe with cosmological constant
- Author
-
Hu, Jinwen and Hu, Huan
- Subjects
General Relativity and Quantum Cosmology ,Astrophysics - Cosmology and Nongalactic Astrophysics ,High Energy Physics - Theory ,83A05 - Abstract
We investigated a bulk viscous fluid universe with cosmological constant {\Lambda} by assuming that the bulk viscosity to be proportional to the Hubble parameter. We found that for an expanding universe, the (relative) matter density will be always greater than a non-zero constant, and tends to this non-zero constant in the future. We show that the bulk viscosity model has a significantly better fitting to the combined SNeIa + CMB + BAO + H(z) data than the {\Lambda}CDM model. Generally, the evolution or values of some cosmological parameters predicted by the bulk viscosity model do not deviate significantly from which are obtained from the {\Lambda}CDM model since the bulk viscosity coefficient obtained from the astronomical observational data is so small. We also made a statefinder analysis of the bulk viscosity model and found that the evolution of the {r, s} parameters behaves in such a way that 0 < s < 1, 0.945 < r <1, indicating the bulk viscosity model is different from the {\Lambda}CDM model., Comment: 17 pages, 6 figures, 3 tables
- Published
- 2024
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