On Cosmological Solutions with Sigma-Model Source

Abstract

A multidimensional model of gravity with a sigma-model action for scalar fields is considered. The gravitational model is defined on the manifold, which contains n Einstein factor spaces. General cosmological-type solutions to the field equations are obtained when n−1 factor-spaces are Ricci-flat. The solutions are defined up to solutions of geodesic equations corresponding to a sigma-model target space. Several examples of sigma-models are considered. A subclass of non-singular solutions is singled-out for the case when all factor-spaces are Ricci-flat.