37 research outputs found
Dynamics of the universe as a "test 3-brane" in a 5D bulk
In this paper we study the dynamics of a 5D bulk space-time with our universe
as a "test 3-brane" located in the bulk, an idealized model of a topological
object whose physical properties is negligible in comparison with that of the
bulk. Our universe experiences acceleration and its equation of state parameter
crosses the phantom divide line due to the geometry of the bulk space-time.Comment: 11 pages, 12 figures; will be published in Can. J. Phy
Curvaton reheating and intermediate inflation in brane cosmology
In this paper, we study the curvaton reheating mechanism for an intermediate
inflationary universe in brane world cosmology. In contrast to our previous
work, we assume that when the universe enters the kination era, it is still in
the high-energy regime. We then discuss, in detail, the new cosmological
constraints on both the model parameters and the physical quantities.Comment: 15 pages, 4 figures. With some modifications to the text the version
published on Can. J. Phys. arXiv admin note: significant text overlap with
arXiv:1011.080
Constraints on scalar-tensor theories from observations
We study the dynamical description of scalar-tensor gravity by performing the
best-fit analysis for two cases of exponential and power-law form of the
potential and scalar field function coupled to the curvature. The models are
then tested against observational data. The results show that in both scenarios
the Universe undergoes an acceleration expansion period and the geometrical
equivalent of dark energy is associated with a time-dependent equation of
state.Comment: 16 pages, 32 figure