Eternal acceleration from M-theory

The dimensional reduction of D-dimensional spacetimes arising in string/M-theory, to the conformal Einstein frame, may give rise to cosmologies with accelerated expansion. Through a complete analysis of the dynamics of doubly warped product spacetimes, in terms of scale invariant variables, it is demonstrated that for D >= 10, eternally accelerating four-dimensional kappa. = -1 Friedmann cosmologies arise from dimensional reduction on an internal space with negative Einstein geometry.