Can Phantom-Dominated Universe Decelerate Also in Future ?
Abstract
Here Randall-Sundrum brane-gravity models of the homogeneous and flat universe, dominated by phantom fluid, is considered. It is noted that brane-gravity corrections effect the behaviour of phantom fluid in RS-II model (where brane-tension is negative) drastically. It is interesting to see that, phantom fluid violates the weak energy condition (WEC) till energy density , but when phantom energy density grows more, the effective equation of state does not violate WEC. Moreover, with increasing phantom energy density, a stage comes when even strong energy condition is not violated due to effect of these corrections. Also expansion stops, when . As a consequence, RS-II phantom universe accelerates upto a finite time explaining the present cosmic acceleration, but it decelerates later.Thus, RS-II phantom universe is singularity-free. In the case of RS-I model, where is positive, characteristics of phantom fluid is not suppressed by brane-corrections and phantom universe accelerates ending up in big-rip singularity in finite future time.
Cite
@article{arxiv.0707.1376,
title = {Can Phantom-Dominated Universe Decelerate Also in Future ?},
author = {S. K. Srivastava},
journal= {arXiv preprint arXiv:0707.1376},
year = {2008}
}
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17 pages