Vertex operator in String Theory on Orbifold: Intertwining Fields between Different Sectors in the Fock Space Representation

Abstract

In the theory of the string on the orbifold different boundary conditions correspond to different Fock spaces (sectors). Using the method of Corrigan and Olive, we introduce a field operator intertwinign these sectors from the condition of duality. The vertex operator for the emission of a particle in a twisted sector is constructed in terms of the above intertwining field.