Finite perturbations on perfect fluid Friedmann-Robertson-Walker models

This paper analyzes the behavior of a family of finite exact perturbations of Friedmann-Robertson-Walker cosmologies constructed with the inverse scattering technique of Belinskii and Zakharov (1978). The application of this method in a five-dimensional spacetime with a massless scalar field and a subsequent Kaluza-Klein dimensional reduction makes it possible to construct models with perfect fluid material content in four dimensions. The behavior of the energy momentum and Weyl tensors are studied as characterizations of the gravitational and material behaviors. The important case of solitonic perturbations on de Sitter backgrounds is also treated. 45 refs