Inhomogeneous cosmological models in scalar-tensor theories

Abstract

Exact self-similar spatially inhomogeneous G2 cosmological models are found in a class of scalar-tensor theories of gravity by exploitingthe formal equivalence of this class of theories (under a conformal transformation and field redefinition) to general relativity minimally coupled to a scalar field with an exponential potential. We argue that theseexact self-similar solutions may play an important role in describingthe asymptotic behaviour (both at early and at late times) of more general scalar-tensorG2 models. The possible isotropization and the homogenization of these models is briefy discussed.