A Study Of The Chaplygin Gas As A Unified Dynamic Model With Interaction

Recently, numerous measurements all suggest that at present the Universeis undergoing cosmic acceleration and is dominated by a dark energy compo-nent with negative pressure. To study dark energy, various dark energy modelshave been constructed. In this paper, based on standard cosmology, we intro-duced some popular dark energy models. Then we worked on the unified dynamicmodel of dark matter and dark energy. We investigated the modified Chaplygingas (MCG)model, studied the evolution of some cosmological quantities, and byanalysis, we found that the state parameter of dark energy wde could cross theso-called phantom divide w = ?1. We also illuminated that the statefinder di-agnostic could discriminate the MCG model and the generalized Chaplygin gas(GCG) model at high redshift other than low redshift. Based on the interactingGCG model advanced by M.C.Bento, we constructed the e?ective equation ofstate (EoS) for dark energy, described the interacting GCG model, and obtainedthe statefinder parameters for the GCG models. Furthermore, we could plot theevolution of the e?ective EoS for dark energy, and therefore realized that thee?ective EoS for dark energy could cross the so-called phantom divide w = ?1.Otherwise, the interacting MCG model has been discussed. By introducing an en-ergy exchange termΓ, we also found that the e?ective EoS for dark energy couldcross the so-called phantom divide w = ?1, and the Universe will not end up withBig Rip in the future. In addition, we guaranteed that the statefinder diagnosticcould discriminate the interacting MCG model and the interacting GCG model.