THE SUPERSYMMETRIC T-J MODEL WITH A BOUNDARY

An open supersymmetric t-J chain with boundary fields is studied by me ans of the Bethe ansatz. Ground state properties for the case of an al most half-filled band and a bulk magnetic field are determined. Bounda ry susceptibilities are calculated as functions of the boundary fields . The effects of the boundary on excitations are investigated by const ructing the exact boundary S-matrix. From the analytic structure of th e boundary S-matrices one deduces that holons can form boundary bound stares for sufficiently strong boundary fields.