Boundary S matrices for the open Hubbard chain with boundary fields

Abstract

Using the method introduced by Grisaru et al., boundary S matrices for the physical excitations of the open Hubbard chain with boundary fields are studied. In contrast to the open supersymmetric t-J model, the boundary S matrix for the charge excitations depend on the boundary fields though the boundary fields do not break the spin-SU(2) symmetry.Comment: Latex,12 page