Cosmological solutions for a model with a1/H2 term

Abstract

We derive the cosmological solutions of a five-dimensional model with a1/H2 term (H2 ≡ HMNPQHMNPQ), where HMNPQ is the 4-form field strength. The behaviours of the scale factors and the scalar potential inthe effective theory are examined. We show that, as a consequence, the universe changesfrom showing decelerated expansion to showing accelerated expansion in the Einstein frameof the four-dimensional theory.