The holographic induced gravity model with a Ricci dark energy: smoothing the little rip and big rip through Gauss-Bonnet effects?

摘要

We present an holographic brane-world model of the Dvali-Gabadadze-Porrati(DGP) scenario with and without a Gauss-Bonnet term (GB) in the bulk. We showthat an holographic dark energy component with the Ricci scale as the infra-redcutoff can describe the late-time acceleration of the universe. In addition, weshow that the dimensionless holographic parameter is very important incharacterising the DGP branches, and in determining the behaviour of the Riccidark energy as well as the asymptotic behaviour of the brane. On the one hand,in the DGP scenario the Ricci dark energy will exhibit a phantom-like behaviourwith no big rip if the holographic parameter is strictly larger than 1/2. Forsmaller values, the brane hits a big rip or a little rip. On the other hand, wehave shown that the introduction of the GB term avoids the big rip and littlerip singularities on both branches but cannot avoid the appearance of a bigfreeze singularity for some values of the holographic parameter on the normalbranch, however, these values are very unlikely because they lead to a verynegative equation of state at the present and therefore we can speak inpractice of singularity avoidance. At this regard, the equation of stateparameter of the Ricci dark energy plays a crucial role, even more importantthan the GB parameter, in rejecting the parameter space where futuresingularities appear.