Accelerated universe with inflation and a divergence-free Big Bang

Abstract

We consider a two-component universe consisting of ordinary matter and vacuum energy quantitatively described by the cosmological term L c = (l/a)ρ c , where l is a quantity having the dimension of length, ρ c is the density of ordinary matter, and a is the scale factor. To justify the form of L c , we use the Maxwell-like approach to gravitation in which it is supposed that the gravitational field energy gravitates. The total energy conservation law for both cosmic components determines the mass density and the vacuum energy density as a function of the scale factor. Applying this two-component cosmic model to the present universe, the important cosmic parameters get values consistent with observations. The ratio of density parameters of ordinary matter and vacuum mass-energy, Ω m /Ω l , in today’s universe is 1/2. Interesting features of our model are (i) the existence of an inflationary phase just at the earliest era of the universe follows directly from the modified Friedmann equations, and (ii) the beginning of cosmic expansion, the Big-Bang, is singularity-free, i.e., both the mass and vacuum energy contents assume finite values at the very origin of the universe.