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TOPIC: Little Rip Cosmology

Blobrana

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Posts: 131433

Date: Jul 14 02:27 2012

Quasi-Rip	Permalink

Title: The Quasi-Rip Authors: Hao Wei, Long-Fei Wang, Xiao-Jiao Guo The fate of our universe is an unceasing topic of cosmology and the human being. The discovery of the current accelerated expansion of the universe significantly changed our view of the fate of the universe. Recently, some interesting scenarios concerning the fate of the universe attracted much attention in the community, namely the so-called "Little Rip" and "Pseudo-Rip". It is worth noting that all the Big Rip, Little Rip and Pseudo-Rip arise from the assumption that the dark energy density rho(a) is monotonically increasing. In the present work, we are interested to investigate what will happen if this assumption is broken, and then propose a so-called "Quasi-Rip" scenario, which is driven by a type of quintom dark energy. In this work, we consider an explicit model of Quasi-Rip in details. We show that Quasi-Rip has an unique feature different from Big Rip, Little Rip and Pseudo-Rip. Our universe has a chance to be rebuilt in the ash after the terrible rip. This might be the last hope in the "hopeless" rip. Read more (133kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jul 26 01:40 2011

Little Rip Cosmology	Permalink

Title: Viscous Little Rip Cosmology Authors: I. Brevik, E. Elizalde, S. Nojiri, S.D. Odintsov 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 under the form of the so-called Little Rip cosmology which appears to be a realistic alternative to the \Lambda CDM 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. Read more (11kb, PDF) __________________

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