PSL(n|n) sigma model as a conformal field theory

We discuss the sigma model on the PSL(n\n) supergroup manifold. We demonstrate that this theory is exactly conformal. The chiral algebra of this model is given by some extension of the Virasoro algebra, similar to the W algebra of Zamolodchikov. We also show that all group invariant correlation functions are coupling constant independent and can be computed in the free theory. The non-invariant correlation functions are highly non-trivial and coupling dependent. At the end we compare two- and three-point correlation functions of the PSL(1, 1\2) sigma model with the correlation functions in the boundary theory of AdS(3) x S-3 and find a qualitative agreement. (C) 1999 Published by Elsevier Science B.V. All rights reserved.