Interacting models of generalized Chaplygin gas and modified Chaplygin gas with barotropic fluid

Abstract

In this paper, we consider two different models of our present universe. We choose the models which consist of different sets of two separate fluids. The first one of each set tries to justify the late time acceleration and the second one is barotropic fluid. The former model considers our present time universe to be homogeneously filled up by Generalized Chaplygin Gas which is interacting with barotropic fluid. On the other hand, the latter model considers that the cosmic acceleration is generated by Modified Chaplygin Gas which is interacting with matter depicted by barotropic equation of state (EoS). For both the models, we consider the interaction term to vary proportionally with Hubble’s parameter as well as with the exotic matter/dark energy’s energy density. We find an explicit function form of the energy density of the cosmos which is found to depend on different cosmological parameters like scale factor, dark energy and barotropic fluid’s EoS parameters and other constants, like interacting constants, etc. We draw curves of effective EoS-s, different cosmological parameters like deceleration parameter q, statefinder parameters r and s with respect to the redshift z (for different values of dark energy and barotropic fluid parameters) and study them thoroughly. We compare two models as well as the nature of dependencies on these models’ interaction coefficients. We point out the particular redshift for which the universe may transit from a deceleration to acceleration phase. We tally all these values with different observational data. Here, we also analyze how this value of particular redshift does change for different values of interaction coefficients and different dark energy models.

Generalized Model of Interacting Dark Energy and Dark Matter : Phase Portrait Analysis of Evolving Universe

“…, a(t) being the scale factor. In the reference [27,28] the interaction kernel is taken as Q = 3Hc i ρ i , where i=DM or DE, after considering the rate of energy transfer is proportional to the energy density of DE or DM and also proportional to H.…”