Aspects of Non-interacting and Interacting Universe: A Complete Scenario

The evolution of the dark energy within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with barotropic fluid and dark energy is examined. We have considered the two cases of an interacting and non-interacting two-fluid (barotropic and dark energy) scenario and obtained the exact solutions to the corresponding field equations. In an interacting model we have considered linear as well as quadratic interaction between dark sector of the universe. We have also given the quadrature form for general interaction coupling parameter via Q = αρmn, n ≥ 1 and discussed the evolution of energy densities and effective equation of state with cosmic time for flat, closed and open universe. It is also examined that the matter energy density is dominated in early phase of the universe where as the dark energy density is dominated in later phase of the universe for both scenarios which is in concurrence with current observations.