2004/08/31 by Hongsu Kim
Physics and Astronomy · #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1016/j.physletb.2004.12.003
published as Phys.Lett. B606 (2005) 223-233 · 18 pages, Accepted for publication in Phys. Lett. B
arxiv created 2004/12/06 · arxiv updated 2009/12/01
In the present work, the Brans-Dicke theory of gravity is taken as a possible theory of k-essence coupled to gravity and then the role played by the Brans-Dicke scalar field in relation to the unified model for dark matter and dark energy is explored. It has been realized that the BD scalar field does indeed play a role of a k-essence, but in a very unique way which distinguishes it from other k-essence fields studied in the literature such as the (generalized) Chaplygin gas or the purely kinetic k-essence studied recently by Scherrer. That is, instead of providing an interpolation between the dark matter-like evolution and the dark energy-like evolution, the BD theory predicts the emergence of a yet-unknown \it zero acceleration epoch which is an intermediate stage acting as a ``crossing bridge'' between the decelerating matter-dominated era and the accelerating phase.