Research On The Theory Of The Unified Model Of Dark Matter And Dark Energy In The Universe

In this paper the characters of dark matter and dark energy are mainly discussed. Based on constructed models of dark matter and dark energy, a parametric symmetric gravitational theory is introduced. By analysis, we can predict that the fate of universe would be Big Rip in the future, and also find that the state parameters of dark energy ω_Φ for the two different constraint conditions are consistent with the present cosmological observations. Then, the ansatz for the Hubble parameter is considered by basis of model-independence advanced by U.Alam. Accordingly, a parametric unified model of dark matter and dark energy is obtained by us. To attain the same aim, on the basis of the generalized Chaplygin gas (GCG), we present the unified equation of state for GCG by the restriction condition. Prom the above two models, we can elaborate the present phenomena and trace back to the past and even predict the future evolution of the universe. Some cosmological quantities such as the fractional contributions of different components of the universe Ω_i (i respectively denotes baryons, dark matter and dark energy) to the critical density, the equation of state for dark energy ω_de, the deceleration parameter q are all obtained, which are consistent with observations. In addition, the transition from deceleration to acceleration is described in our models. Besides, it is denied in our models that our universe will end up with Big Rip in the future.