Viscous cosmologies with extra dimensions

Abstract

We present an analysis of a n-dimensional vacuum Einstein field equations in which 4-dimensional space-time is described by a Friedmann Robertson- Walker (FRW) metric and that of the extra dimensions by a Kasner type Euclidean metric. The field equations are interpreted as four dimensional Einstein equations with effective matter properties. The effective matter is then treated as viscous fluid. We consider the theories of imperfect fluid given by Eckart, truncated Israel-Stewart and full Israel-Stewart theories and obtain cosmological solutions for a flat model of the universe. The imperfect fluid assumption admits here power law inflation for the 3-physical space in some cases.