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

Abstract

Main aim of this work is to give a suitable explanation of present accelerating universe through an acceptable interactive dynamical cosmological model. A three-fluid cosmological model is introduced in the background of Friedmann-Lema\^itre-Robertson-Walker asymptotically flat spacetime. This model consists of interactive dark matter and dark energy with baryonic matter taken as perfect fluid satisfying barotropic equation of state. We consider dust as the candidate of dark matter. A scalar field $\phi$ represents dark energy with potential $V(\phi)$. Einstein's field equations are utilised to construct a three-dimensional interactive autonomous system by choosing suitable interaction between dark energy and dark matter. We take the interaction kernel as $Q = 3\beta^{2\gamma} H\rho_d$. In order to explain the stability of this system, we obtained some suitable critical points. We analyse stability of obtained critical points to show the different phases of universe and cosmological implications. Surprisingly, we find some stable critical points which represent late time dark energy dominated era when a model parameter $\alpha=-5.05$. In order to explain both the energy dominated era as well as the late-time acceleration of the universe at same time, we introduce a two-dimensional interactive autonomous system. After graphical analysis of two-dimensional system, we get several stable points which represent dark energy dominated era and the late-time cosmic acceleration both at the same time. We also show the variation in interaction at vicinity of phantom barrier ($\omega_{eff}=-1$). From our work we can also predict the future phase evolution of the universe. No tendency for future deceleration is detected so far.