Some exact results for the multicomponent t-J model

We present a generalization of the Sutherland multicomponent model. Our extension includes both the ferromagnetic and the antiferromagnetic t-J model for any value of the exchange coupling J and the hopping parameter t. We prove rigorously that for one-dimensional chains the ground state of the generalized model is nondegenerate. As a consequence, the ordering of energy levels of the antiferromagnetic t-J model is determined. Our result rigorously proves and extends the analysis carried out by Sutherland in establishing the phase diagram of the model as a function of the number of components.