Gauged WZW Models and the Coset Construction of Conformal Field Theories

The gauged Wess-Zumino-Witten models are shown to be conformal field theories providing field theoretic realizations for the Goddard-Kent- Olive coset construction G/H. In particular the conformai charge of the model coincides with the one obtained in the GKO construction. The physical spectrum of the gauged WZW model is analyzed in the BRST framework. We discuss how the physical states implement unitary representations of the coset Virasoro algebra. When H is the Cartan subalgebra of G the BRST invariant current operators (the physical currents) are shown to be the parafermionic currents.