Duality and O(d, d) symmetries in string theory

Abstract

The evolution of a closed bosonic string is envisaged in the time-dependent background of its massless modes. A duality transformation is implemented on the spatial component of string coordinates to obtain a dual string. It is shown that the evolution equations are manifestly O(d, d) invariant. The tree level string effective actions for the original and the dual string theory are shown to be equivalent.