Anisotropic SD2 brane: accelerating cosmology and Kasner-like space-time from compactification

Abstract

Abstract Starting from an anisotropic (in all directions including the time direction of the brane) non-SUSY D2 brane solution of type IIA string theory we construct an anisotropic space-like D2 brane (or SD2 brane, for short) solution by the standard trick of a double Wick rotation. This solution is characterized by five independent parameters. We show that compactification on six-dimensional hyperbolic space (H $$_6$$ 6 ) of a time-dependent volume of this SD2 brane solution leads to accelerating cosmologies (for some time $$t\sim \,t_0$$ t ∼ t 0 , with $$t_0$$ t 0 some characteristic time) where both the expansions and the accelerations are different in three spatial directions of the resultant four-dimensional universe. On the other hand at early times ( $$t \ll t_0$$ t ≪ t 0 ) this four-dimensional space, in certain situations, leads to four-dimensional Kasner-like cosmology, with two additional scalars, namely, the dilaton and a volume scalar of H $$_6$$ 6 . Unlike in the standard four-dimensional Kasner cosmology here all three Kasner exponents could be positive definite, leading to expansions in all three directions.