Infinite-Dimensional Symmetries of Two-Dimensional Coset Models Coupled to Gravity

Abstract

In an earlier paper we studied the infinite-dimensional symmetries of symmetric-space sigma models (SSMs) in a flat two-dimensional spacetime. Here, we extend our investigation to the case of two-dimensional SSMs coupled to gravity. These theories arise from the toroidal reduction of higher-dimensional gravity and supergravities to two dimensions. We construct explicit expressions for the symmetry transformations under the affine Kac-Moody extension $\hat G$ that arises when starting from a G/H coset model. We also construct further explicit symmetry transformations that correspond to the modes L_n of a Virasoro subalgebra with $n\ge -1$.