Crossing the cosmological constant line in a dilatonic brane-world model with and withoutcurvature corrections

Abstract

We construct a new brane-world model composed of a bulk with a dilatonic field, plus abrane with brane tension coupled to the dilaton, cold dark matter and an induced gravityterm. It is possible to show that, depending on the nature of the coupling between thebrane tension and the dilaton, this model can describe the late time acceleration of thebrane expansion (for the normal branch) as it moves within the bulk. The acceleration isproduced together with a mimicry of the crossing of the cosmological constant line(w = −1) on the brane, although this crossing of the phantom divide is obtained withoutinvoking any phantom matter either on the brane or in the bulk. The role of darkenergy is played by the brane tension, which reaches a maximum positive valuealong the cosmological expansion of the brane. It is precisely at that maximumthat the crossing of the phantom divide takes place. We also show that theseresults remain valid when the induced gravity term on the brane is switchedoff.