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Title
Abstract
Introduction
Case with Ζ 0 = 0
Discussion
Proofs JCAP_068P_0313 6 Conclusion
Remarks on Phase Space Analysis
References

Bulk viscous matter-dominated Universes: asymptotic properties

Profile image of Israel QuirosIsrael Quiros

2013, Journal of Cosmology and Astroparticle Physics

https://doi.org/10.1088/1475-7516/2013/08/012
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30 pages

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Abstract

By means of a combined use of the type Ia supernovae and H(z) data tests, together with the study of the asymptotic properties in the equivalent phase space -through the use of the dynamical systems tools -we demonstrate that the bulk viscous matterdominated scenario is not a good model to explain the accepted cosmological paradigm, at least, under the parametrization of bulk viscosity considered in this paper. The main objection against such scenarios is the absence of conventional radiation and matter-dominated critical points in the phase space of the model. This entails that radiation and matter dominance are not generic solutions of the cosmological equations, so that these stages can be implemented only by means of unique and very specific initial conditions, i. e., of very unstable particular solutions. Such a behavior is in marked contradiction with the accepted cosmological paradigm which requires of an earlier stage dominated by relativistic species, followed by a period of conventional non-relativistic matter domination, during which the cosmic structure we see was formed. Also, we found that the bulk viscosity is positive just until very late times in the cosmic evolution, around z < 1. For earlier epochs it is negative, been in tension with the local second law of thermodynamics.

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Prepared for submission to JCAP Bulk Viscous Matter-dominated Universes: Asymptotic Properties
Israel Quiros

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