String Cosmological Solutions with O(d, d) Duality Symmetry and Matter Coupling

The duality properties of string cosmology model with negative energy matter are investigated by means of renormalization group equation, the cosmological solutions with exotic matter coupling are obtained in D = d + 1 dimensional space-time. These inflation-power solutions can describe accelerated and decelerated process in the early universe, and the duality solutions can be generated through O(d, d) transformations.