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On time-dependent black holes and cosmological models from a Kaluza-Klein mechanish

Abstract:

Novel static, time-dependent and spatial-temporal solutions to Einstein field equations, displaying singularities, with and without horizons, and in several dimensions, are found based on a dimensional reduction procedure widely used in Kaluza-Klein-type theories. The Kerr-Newman black hole entropy as well as the Reissner-Nordstrom, Kerr and Schwarzschild black hole entropy are derived from the corresponding Euclideanized actions. A very special cosmological model based on the dynamical interior geometry of a black hole is found that has no singularities at t = 0 due to the smoothing of the mass distribution. We conclude with another cosmological model equipped also with a dynamical horizon and which is related to Vaidya's metric (associated with the Hawking radiation of black holes) by interchanging t ↔ r, which might render our universe a dynamical black hole. © 2009 World Scientific Publishing Company.