Electric S-brane solutions corresponding to rank-2 Lie algebras: Acceleration and small variation of G

Abstract

Electric S-brane solutions with two non-composite electric branes and a set of l scalar fields are considered. The intersection rules for branes correspond to Lie algebras A2, C2 and G2. The solutions contain five factor spaces. One of them, M0, is interpreted as our 3-dimensional space. It is shown that there exists a time interval where accelerated expansion of our 3-dimensional space is compatible with a small enough variation of the effective gravitational constant G(τ). This interval contains τ0, a point of minimum of the function G(τ). A special solution with two phantom scalar fields is analyzed, and it is shown that, in the vicinity of the point τ0, the time variation of G(τ) (calculated in the linear approximation) decreases in the sequence of Lie algebras A2, C2 and G2.