Date: June 19,  2002
Time : 15:30 - 16:00
Place : Sternberg Astronomical Institute, Conference Hall
Name : Sergey Chervon
Institute : Uliyanovsk State University
Title : Cosmological Models of Global Universe Evolution and Cosmological Perturbations
Abstract :Cosmological models, based on the self-interacting scalar field theory or on the theory of the chiral nonlinear sigma model, presented as the models which can describe the global evolution, extending from an inflationary stage to the present time epoch, of the Universe.  
The general properties of the evolution of a homogeneous isotropicuniverse are considered on the basis of an analysis of the system of Einstein equations for a self-inter\-acting scalar and chiral fields. One of the important requirements imposed on the universe evolution by present-day observational data is the existence of an inflationary phase in the very early stage and at present day epoch. Thus the morden general consept of universe's evolution include the
evolution from the Planck's epoch through an inflationary stage which should be ended by exit to radiation era and then to matter dominated epoch to the present-day universe which obey an inflationary expantion. The exact solution, admitting an analytical exit from inflationary stage into a radiation era and a matter dominated epoch are discussed. The result is obtained by virtue of ``fine turning of the potential'' method and by the analysis of some correspondence between exact solutions and
approximate ones in slow roll regim. We found that an inflationary stage is supported by decay of higgs bosons in the framework of the solution obtained. Freidmann's regim is associated with adiabatical expantion of the Universe, filled by the matter with special equation of state.
The scalar perturbations for the chiral cosmological model of the homogeneous and isotropic Universe are considered in details. The method for the scalar perturbations decomposition for inflaton and non-inflaton perturbations is proposed.


Date:June 20,  2002
Time: 12:15 - 13:15
Place : Lebedev  Physical Institute
Name: Sergey Chervon
Institute : Uliyanovsk State University
Title : Non-linear sigma models in gravitation and cosmology