Qualitative Properties of Scalar-Tensor Theories of Gravity

The qualitative properties of spatiallyhomogeneous stiff perfect fluid and minimally coupledmassless scalar field models within general relativityare discussed. Consequently, by exploiting the formal equivalence under conformal transformations and field redefinitions of certain classes of theories ofgravity, the asymptotic properties of spatiallyhomogeneous models in a class of scalar-tensor theories of gravity that includes the Brans-Dicke theory can be determined. For example, exact solutions are presented, which are analogues of the general relativistic Jacobs stiff perfect fluid solutions andvacuum plane wave solutions, which act as past andfuture attractors in the class of spatially homogeneousmodels in Brans-Dicke theory.