Two-component cosmological models with a variable equation of state of matter and with thermal equilibrium of components

A class of models describing the evolution of the homogeneous and isotropic spatially flat Universe filled with a scalar field and matter and changing the equation of state during its evolution from a vacuum-like form to an i deal liquid is proposed under the assumption that both components of matter are in thermal equilibrium. The main characteristics of such models are an alyzed and their asymptotic behavior in the vicinity of a cosmological sing ularity and at the postinflation stage is investigated. It is shown that th e thermal equilibrium condition and the requirement of asymptotic decrease of the field with time unambiguously lead to secondary inflation at the fin al stage of evolution, which is accompanied by accelerated expansion of the Universe and an increase in the temperature of matter. (C) 2001 MAIK "Nauk a/Interperiodica".