2011/07/31 by I. Brevik, E. Elizalde, S. Nojiri +1 · 1 citation
Physics and Astronomy · #hep-th #astro-ph.CO #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.84.103508
10 pages, version to appear in PRD
arxiv created 2011/10/14 · arxiv updated 2013/05/29
Dark energy of phantom or quintessence nature with an equation of state parameter w almost equal to -1 often leads the universe evolution to a finite-time future singularity. An elegant solution to this problem has been recently proposed \citeframpton11 under the form of the so-called Little Rip cosmology which appears to be a realistic alternative to the ΛCDM model. A viscous Little Rip cosmology is here proposed. Whereas generically bulk viscosity tends to promote the Big Rip, we find that there are a number of situations where this is not the case and where the formalism nicely adjusts itself to the Little Rip scenario. We prove, in particular, that a viscous fluid (or, equivalently, one with an inhomogeneous (imperfect) equation of state) is perfectly able to produce a Little Rip cosmology as a purely viscosity effect. The possibility of its induction as a combined result of viscosity and a general (power-like) equation of state is also investigated in detail. To finish, a physical, inertial force interpretation of the dissolution of bound structures in the Little Rip cosmology is presented.