Particle creation in varying speed of light cosmological models

Abstract

Einstein's field equations with a variable speed of light c = c(t), gravitational coupling G = G(t) and decaying vacuum energy density = (t) are considered as describing matter creation in a cosmological framework. The particle creation rate is uniquely determined by the variation rates of c, G and . By considering simple phenomenological evolution laws for the `constants', exact analytical and numerical solutions of the gravitational field equations are obtained for a homogeneous and isotropic Friedmann-Robertson-Walker spacetime leading to a self-consistent cosmological model describing matter and entropy generation in the very early Universe.