On the Role of Viscosity in Early Cosmology
| dc.creator | Carlevaro, Nakia | |
| dc.creator | Montani, Giovanni | |
| dc.date | 2008-01-22 | |
| dc.date | 2008-04-24 | |
| dc.date.accessioned | 2026-07-07T12:55:01Z | |
| dc.date.available | 2026-07-07T12:55:01Z | |
| dc.description | We present a discussion of the effects induced by bulk viscosity on the very early Universe stability. The viscosity coefficient is assumed to be related to the energy density $ρ$ via a power-law of the form $ζ=ζ_0 ρ^s$ (where $ζ_0, s=const.$) and the behavior of the density contrast in analyzed. In particular, we study both Einstein and hydrodynamic equations up to first and second order in time in the so-called quasi-isotropic collapsing picture near the cosmological singularity. As a result, we get a power-law solution existing only in correspondence to a restricted domain of $ζ_0$. The particular case of pure isotropic FRW dynamics is then analyzed and we show how the asymptotic approach to the initial singularity admits an unstable collapsing picture. | |
| dc.description | 4 pages, no figure | |
| dc.identifier | https://arxiv.org/abs/0801.3368 | |
| dc.identifier | http://arxiv.org/abs/0801.3368 | |
| dc.identifier | Int. J. Mod. Phys. A 23, 1248-1252 (2008) | |
| dc.identifier | doi:10.1142/S0217751X08040160 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/224137 | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.subject | Astrophysics | |
| dc.title | On the Role of Viscosity in Early Cosmology | |
| dc.type | text |