Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
Abstract
We review different dark energy cosmologies. In particular, we present the ΛCDM cosmology, Little Rip and PseudoRip universes, the phantom and quintessence cosmologies with Type I, II, III and IV finitetime future singularities and nonsingular dark energy universes. In the first part, we explain the ΛCDM model and wellestablished observational tests which constrain the current cosmic acceleration. After that, we investigate the dark fluid universe where a fluid has quite general equation of state (EoS) [including inhomogeneous or imperfect EoS]. All the above dark energy cosmologies for different fluids are explicitly realized, and their properties are also explored. It is shown that all the above dark energy universes may mimic the ΛCDM model currently, consistent with the recent observational data. Furthermore, special attention is paid to the equivalence of different dark energy models. We consider single and multiple scalar field theories, tachyon scalar theory and holographic dark energy as models for current acceleration with the features of quintessence/phantom cosmology, and demonstrate their equivalence to the corresponding fluid descriptions. In the second part, we study another equivalent class of dark energy models which includes F( R) gravity as well as F( R) HořavaLifshitz gravity and the teleparallel f( T) gravity. The cosmology of such models representing the ΛCDMlike universe or the accelerating expansion with the quintessence/phantom nature is described. Finally, we approach the problem of testing dark energy and alternative gravity models to general relativity by cosmography. We show that degeneration among parameters can be removed by accurate data analysis of large data samples and also present the examples.
 Publication:

Astrophysics and Space Science
 Pub Date:
 November 2012
 DOI:
 10.1007/s1050901211818
 arXiv:
 arXiv:1205.3421
 Bibcode:
 2012Ap&SS.342..155B
 Keywords:

 Modified theories of gravity;
 Dark energy;
 Cosmology;
 General Relativity and Quantum Cosmology;
 Astrophysics  Cosmology and Extragalactic Astrophysics;
 High Energy Physics  Theory
 EPrint:
 160 pages, 4 figures, Invited Review, to appear in Astrophysics and Space Science