Friday, January 4, 2013

1301.0418 (Alvina Burgazli et al.)

Can quintessence and phantom cause the late time acceleration of the Universe?    [PDF]

Alvina Burgazli, Maxim Eingorn, Alexander Zhuk
In this Letter, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Supposing that the Universe contains also the cosmological constant and quintessence/phantom fluids with the constant equation of state parameter $\omega$, we investigate scalar perturbations of the FRW metrics due to inhomogeneities. Our analysis shows that, to be compatible with the theory of scalar perturbations, the quintessence/phantom, first, should be clustered and, second, should have the equation of state parameter $\omega=-1/3$. Therefore, this quintessence neither accelerates nor decelerates the Universe. We also obtain the equation for the nonrelativistic gravitational potential created by a system of inhomogeneities. Due to the quintessence, the physically reasonable solutions take place for flat, open and closed Universes. Quintessence is concentrated around the inhomogeneities and results in screening of the gravitational potential.
View original: http://arxiv.org/abs/1301.0418

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