Escaping the big rip?
Abstract
We discuss dark energy models which might describe effectively the actual acceleration of the universe. More precisely, for a fourdimensional Friedmann Lemaître Robertson Walker (FLRW) universe we consider two situations. For the first of them, we model dark energy as phantom energy described as a perfect fluid satisfying the equation of state P = (β1)ρ (with β<0 and constant). In this case the universe reaches a 'big rip' independently of the spatial geometry of the FLRW universe. In the second situation, the dark energy is described as a phantom (generalized) Chaplygin gas which violates the dominant energy condition. Contrary to the previous case, for this material content a FLRW universe would never reach a 'big rip' singularity (indeed, the geometry is asymptotically de Sitter). We also show how this dark energy model can be described in terms of scalar fields, corresponding to a minimally coupled scalar field, a Born Infeld scalar field and a generalized Born Infeld scalar field. Finally, we introduce a phenomenologically viable model where dark energy is described as a phantom generalized Chaplygin gas.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 May 2005
 DOI:
 10.1088/14757516/2005/05/005
 arXiv:
 arXiv:astroph/0404540
 Bibcode:
 2005JCAP...05..005B
 Keywords:

 Astrophysics
 EPrint:
 12 pages, 11 figures, RevTeX 4