Dark energy: Vacuum fluctuations, the effective phantom phase, and holography
Abstract
We aim at the construction of dark energy models without exotic matter but with a phantomlike equation of state (an effective phantom phase). The first model we consider is decaying vacuum cosmology where the fluctuations of the vacuum are taken into account. In this case, the phantom cosmology (with an effective, observational ω being less than 1 ) emerges even for the case of a real dark energy with a physical equation of state parameter ω larger than 1. The second proposal is a generalized holographic model, which is produced by the presence of an infrared cutoff. It also leads to an effective phantom phase, which is not a transient one as in the first model. However, we show that quantum effects are able to prevent its evolution towards a big rip singularity.
 Publication:

Physical Review D
 Pub Date:
 May 2005
 DOI:
 10.1103/PhysRevD.71.103504
 arXiv:
 arXiv:hepth/0502082
 Bibcode:
 2005PhRvD..71j3504E
 Keywords:

 98.80.k;
 04.50.+h;
 04.60.m;
 11.25.w;
 Cosmology;
 Gravity in more than four dimensions KaluzaKlein theory unified field theories;
 alternative theories of gravity;
 Quantum gravity;
 Strings and branes;
 High Energy Physics  Theory;
 Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 13 pages, 2 figures, revtex4, version to appear in Physical Review D