Abstract
The generalized Chaplygin gas is characterized by the equation of state , with and . We generalize this model to allow for the cases where or . This generalization leads to three new versions of the generalized Chaplygin gas: an early phantom model in which at early times and asymptotically approaches at late times, a late phantom model with at early times and at late times, and a transient model with at early times and at late times. We consider these three cases as models for dark energy alone and examine constraints from type Ia supernovae and from the subhorizon growth of density perturbations. The transient Chaplygin gas model provides a possible mechanism to allow for a currently accelerating universe without a future horizon, while some of the early phantom models produce without either past or future singularities.
2 More- Received 29 July 2005
DOI:https://doi.org/10.1103/PhysRevD.72.063511
©2005 American Physical Society