Brans - Dicke 's Theory Of Holographic Origin Interaction In Time - Dependent Cosmological Constants

The observations from supernovae of type Ia cosmic microwave background radiationand SDSS indicate that the universe is undergoing accelerated expansion. Investigating thereason why universe is accelerating becomes a hotspot for astrophysical scholars. Usually,the accelerated universe is interpreted by two aspects: one is that it is considered that there isthe dark energy component in universe, the other is thought that the Einstein’s equationshould be modified.At firstly, we introduce the main equations of modern cosmology. And then some darkenergy models is briefly described. Furthermore, we study the time variable cosmologicalconstant of holographic origin with interaction in Brans-Dicke theory. We investigate somecharacters for this model. In discussion, we investigate the relation between cosmologicalquantities and model parameters, and compare the difference between Brans-Dicke theoryand Einstein’s theory. Also, the difference between with interaction and without interaction indark components is studied. It is shown that in this scenario an accelerating universe can beobtained and the evolution of state parameter for dark energy can cross over the boundary ofphantom divide. In addition, a geometrical diagnostic method, jerk parameter, is applied tothis model to distinguish it with cosmological constant.