EXACT SOLUTION FOR A DEGENERATE ANDERSON IMPURITY IN THE U-]INFINITY LIMIT EMBEDDED INTO A CORRELATED HOST

We consider the one-dimensional t-J model, which consists of electrons with spin S on a lattice with nearest neighbor hopping t constrained by the excluded multiple occupancy of the lattice sites and spin-excha nge J between neighboring sites. The model is integrable at the supers ymmetric point, J = t. Without spoiling the integrability we introduce an Anderson-like impurity of spin S (degenerate Anderson model in the U --> infinity limit), which interacts with the correlated conduction states of the host. The lattice model is defined by the scattering ma trices via the Quantum Inverse Scattering Method. We discuss the gener al form of the interaction Hamiltonian between the impurity and the it inerant electrons on the lattice and explicitly construct it in the co ntinuum limit. The discrete Bethe ansatz equations diagonalizing the h ost with impurity are derived, and the thermodynamic Bethe ansatz equa tions are obtained using the string hypothesis for arbitrary band fill ing as a function of temperature and external magnetic field. The prop erties of the impurity depend on one coupling parameter related to the Kondo exchange coupling. The impurity can localize up to one itineran t electron and has in general mixed valent properties. Groundstate pro perties of the impurity, such as the energy, valence, magnetic suscept ibility and the specific heat gamma coefficient, are discussed. In the integer valent limit the model reduces to a Coqblin-Schrieffer impuri ty.