Abstract
We investigate the properties of a cosmological scenario which undergoes a gravitational phase transition at late times. In this scenario, the Universe evolves according to general relativity in the standard, hot big bang picture until a redshift . Nonperturbative phenomena associated with a minimally-coupled scalar field catalyzes a transition, whereby an order parameter consisting of curvature quantities such as , , acquires a constant expectation value. The ensuing cosmic acceleration appears driven by a dark-energy component with an equation-of-state . We evaluate the constraints from type 1a supernovae, the cosmic microwave background, and other cosmological observations. We find that a range of models making a sharp transition to cosmic acceleration are consistent with observations.
1 More- Received 4 August 2005
DOI:https://doi.org/10.1103/PhysRevD.73.023513
©2006 American Physical Society