Bosonic realization of N=2 super-conformal algebras

We present a simple bosonic realization of the discrete series unitary representations of the two-dimensional N=2 super-conformal algebras. This is obtained by considering index k embeddings of SU(2) into other Lie algebras. For the simplest such embedding one can obtain the complete set of highest weight states as combinations of momentum states of the bosons. This realization is used to analyse the k=4 model in detail. We also discuss how the techniques presented here can be used to understand, in terms of orbifolds, many of the string theories assembled via representations of N=2 super-conformal discrete series. (orig.)