Accelerating multidimensional cosmologies

by Zhuk, Alexander (Odessa University)

Thursday 8 Mar 2007, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

Multidimensional cosmological models with factorizable geometry are analyzed as regards the possibility of their accelerating the expansion of our Universe. First, we consider multidimensional models with stable compactification of the internal spaces. The characteristic feature of these models is that effective dark energy coincides with the observable one provided that the parameters of the models are extremely fine tuned. We demonstrate this problem for the case of a non-linear action R + 1/R + form-fields. For this particular model we show additionally a possibility for creation of non-inflating cosmic domain walls. Second, we investigate accelerating models with dynamical internal spaces. For this purpose, we consider Sp-brane solutions. Here, we present z-dependence of the late-time acceleration of our Universe. However, the typical problem for this class of models is too large a variation of the effective fine structure constant.