A note on the IR limit of the NLIEs of boundary supersymmetric sine-Gordon model

Abstract: We consider the infrared (IR) limit of the nonlinear integral equations (NLIEs) for the boundary supersymmetric sine-Gordon (BSSG) model, previously obtained from the NLIEs for the inhomogeneous open spin-1 XXZ quantum spin chain with general integrable boundary terms, for values of the boundary parameters which satisfy a certain constraint. In particular, we compute the boundary S matrix and determine the "lattice - IR" relation for the BSSG parameters.