Decaying vacuum and evolution from early inflation to late acceleration

Abstract

Decaying vacuum models are a class of models that incorporate the vacuum energy density as a time-evolving entity that has the potential to explain the entire evolutionary history of the universe in a single framework. A general solution to the Friedmann equation can be obtained by considering vacuum energy density as a function of the Hubble parameter. We have obtained the asymptotic solution by choosing the appropriate equation of state for matter and radiation. Finite boundaries in the early and late de Sitter epoch could be defined by considering the evolution of primordial perturbation wavelength. An epoch invariant number $N_c$ determines the number of perturbation modes that cross the Hubble radii during each epoch has been obtained.