8,470 research outputs found
A primer on problems and prospects of dark energy
This review on dark energy is intended for a wider audience, beginners as
well as experts. It contains important notes on various aspects of dark energy
and its alternatives. The section on Newtonian cosmology followed by heuristic
arguments to capture the pressure effects allows us to discuss the basic
features of physics of cosmic acceleration without actually resorting to the
framework of general theory of relativity. The brief discussion on
observational aspects of dark energy is followed by a detailed exposition of
underlying features of scalar field dynamic relevant to cosmology. The review
includes pedagogical presentation of generic features of models of dark energy
and its possible alternatives.Comment: 23 pages and 10 figures,invited review for Curr. Sci, final versio
Implementing Power Law Inflation with Tachyon Rolling on the Brane
We study a minimally coupled tachyon field rolling down to its ground state
on the FRW brane. We construct tacyonic potential which can implements power
law inflation in the brane world cosmology. The potential turns out to be on the brane and reduces to inverse square potential at late times
when brane corrections to the Friedmann equation become negligible. We also do
similar exercise with a normal scalar field and discover that the inverse
square potential on the brane leads to power law inflation.Comment: RevTeX, 4 pages, New references adde
Background cosmological dynamics in gravity and observational constraints
In this paper, we carry out a study of viable cosmological models in
-gravity at the background level. We use observable parameters like
and to form autonomous system of equations and show that the
models under consideration exhibit two different regimes in their time
evolution, namely, a phantom phase followed by a quintessence like behavior. We
employ statefinder parameters to emphasize a characteristic discriminative
signature of these models.Comment: 6 pages, Latex style, 9 eps figures, replaced versions with new
references added, Submitted to Phys.Rev.
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