Astronomy and Astrophysics – Astrophysics – General Relativity and Quantum Cosmology
Scientific paper
2003-05-11
Class.Quant.Grav.20:5321-5341,2003
Astronomy and Astrophysics
Astrophysics
General Relativity and Quantum Cosmology
Few comments added, references updated. To appear in Classical and Quantum Gravity
Scientific paper
10.1088/0264-9381/20/24/006
We investigate the cosmological consequences of a brane-world theory which incorporates time variations in the gravitational coupling G and the cosmological term Lambda. We analyze in detail the model where (dG/dt)/G ~ H and Lambda ~ H^2, which seems to be favored by observations. We show that these conditions single out models with flat space sections. We determine the behavior of the expansion scale factor, as well as, the variation of G, Lambda and H for different possible scenarios where the bulk cosmological constant can be zero, positive or negative. We demonstrate that the universe must recollapse, if it is embedded in an Anti-de Sitter five-dimensional bulk, which is the usual case in brane models. We evaluate the cosmological parameters, using some observational data, and show that we are nowhere near the time of recollapse. We conclude that the models with zero and negative bulk cosmological constant agree with the observed accelerating universe, while fitting simultaneously the observational data for the density and deceleration parameters. The age of the universe, even in the recollapsing case, is much larger than in the FRW universe.
No associations
LandOfFree
Brane-Universes with Variable G and Lambda does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Brane-Universes with Variable G and Lambda, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brane-Universes with Variable G and Lambda will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-202296