The quantum superstring as a WZNW model with N=2 superconformal symmetry Original Research Article

We present a new development in our approach to the covariant quantization of superstrings in 10 dimensions which is based on a gauged WZNW model. To incorporate worldsheet diffeomorphisms we need the quartet of ghosts (bzz,cz,βzz,γz) for topological gravity. The currents of this combined system form an N=2 superconformal algebra. The model has vanishing central charge and contains two anticommuting BRST charges, QS=QW+∮γzbzz and QV=∮cz(TWzz+(1/2)Ttopzz)+γz(BWzz+(1/2)Btopzz−(1/2)czFzzz−(1/4)γzΦzzz). Physical states form the cohomology of QS+QV+∮ηz, where ηz is obtained by the usual fermionization of βzz,γz, have non-negative grading, and are annihilated by b0 and β0. We no longer introduce any ghosts by hand, and the formalism is completely Lorentz covariant.