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 $\lambda$ is negative) drastically. It is interesting to see that, phantom fluid violates the weak energy condition (WEC) till energy density $\rho <\lambda$, but when phantom energy density $\rho$ 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 $\rho =2\lambda$. 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 $\lambda$ 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.

17 pages

References in corpus (1)

• Chaplygin DGP cosmologies

Cited by in corpus (2)

• The nature of cosmological singularities in isotropic universes and braneworlds
• Non-linear Equation of State, COSMIC Acceleration and Deceleration During Phantom-Dominance