### Late acceleration and $w=-1$ crossing in induced gravityLate acceleration and $w=-1$ crossing in induced gravity

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 Author Apostolopoulos, Pantelis S. ♦ Tetradis, Nikolaos Source arXiv.org Content type Text File Format PDF Date of Submission 2006-04-03 Language English
 Subject Domain (in DDC) Computer science, information & general works ♦ Natural sciences & mathematics ♦ Astronomy & allied sciences ♦ Physics Subject Keyword High Energy Physics - Theory ♦ Astrophysics ♦ General Relativity and Quantum Cosmology ♦ physics:astro-ph ♦ physics:gr-qc ♦ physics:hep-th Abstract We study the cosmological evolution on a brane with induced gravity within a bulk with arbitrary matter content. We consider a Friedmann-Robertson-Walker brane, invariantly characterized by a six-dimensional group of isometries. We derive the effective Friedmann and Raychaudhuri equations. We show that the Hubble expansion rate on the brane depends on the covariantly defined integrated mass in the bulk, which determines the energy density of the generalized dark radiation. The Friedmann equation has two branches, distinguished by the two possible values of the parameter $\ex=\pm 1$. The branch with $\ex=1$ is characterized by an effective cosmological constant and accelerated expansion for low energy densities. Another remarkable feature is that the contribution from the generalized dark radiation appears with a negative sign. As a result, the presence of the bulk corresponds to an effective negative energy density on the brane, without violation of the weak energy condition. The transition from a period of domination of the matter energy density by non-relativistic brane matter to domination by the generalized dark radiation corresponds to a crossing of the phantom divide $w=-1$. Description Reference: Phys.Rev.D74:064021,2006 Educational Use Research Learning Resource Type Article Page Count 7