Escaping the Big Rip?
Loading...
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
We discuss dark energy models which might describe effectively the actual acceleration of the universe. More precisely, for a 4-dimensional Friedmann-Lema\^ıtre-Robertson-Walker (FLRW) universe we consider two situations: First of them, we model dark energy by phantom energy described by a perfect fluid satisfying the equation of state $P=(β-1)ρ$ (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 by 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 by a phantom generalized Chaplygin gas.
12 pages, 11 figures, RevTeX 4
12 pages, 11 figures, RevTeX 4