SU(2) x SU(2) invariant scattering matrix of the Hubbard model

We consider the one-dimensional half-filled Hubbard model. We show that the excitation spectrum is given by the scattering states of four elementary excitations, which form the fundamental representation of SU(2)xSU(2). We determine the exact two-particle Scattering matrix, which a solution of the Yang-Baxter equation and reflects the SO(4) symmetry of the model. The results for repulsive and attractive Hubbard model are related by an interchange of spin and charge degrees of freedom. (orig.)SIGLEAvailable from TIB Hannover: RN 5063(93-39) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman