CHIRAL VERTEX OPERATORS IN OFF-CONFORMAL THEORY - SINE-GORDON EXAMPLE

We study chiral vertex operators in sine-Gordon (SG) theory, viewed as an off-conformal system. We find that these operators, which would ha ve been primary fields in the conformal limit, have interesting proper ties in the SG model. Some of them commute with the cosine interaction term in the Hamiltonian at a finite separation. Their Heisenberg equa tions of motion are local in space. An example of such vertex operator s is Mandelstam's bosonic representation of the Fermi field. Another e xample is a set of vertex operators of topological number 2. We show h ow to construct conserved nonlocal currents from these operators. In t he presence of the nonconformal interactions, these nonlocal currents have unique Lorentz spins.