Cosmological Van Der Waals Model with Viscosity in an Inflationary Universe

Abstract

The evolution of the Universe in the early (inflationary) stage of its development in the spatially flat Friedmann–Lemaître–Robertson–Walker metric is considered. A theoretical model, described by a van der Waals fluid with the effect of bulk viscosity taken into account is investigated. A solution of the gravitation equation for the energy density is found and an analytical expression for the scale factor has been obtained. To verify the reliability of the cosmological model, the inflation parameters, the spectral index, and the scalartensor ratio were calculated. A comparison of these parameters with data obtained from observations of the Planck satellites is carried out. Conditions for the applicability of the van der Waals model with viscosity to the description of an inflationary Universe are obtained.