Chaos in Robertson-Walker cosmology

Chaos in Robertson-Walker cosmological models where gravity is coupled to o ne or more scalar fields has been studied by a few authors, mostly using nu merical simulations. In this paper we begin a systematic study of the analy tical aspect. We consider one conformally coupled scalar field and, using t he fact that the model is integrable when the field is massless, we show in detail how homoclinic chaos arises for nonzero masses using a perturbative method. (C) 1998 American Institute of Physics. [S0022-2488(98)00511-8].