AN EXACTLY SOLVABLE KONDO PROBLEM FOR INTERACTING ONE-DIMENSIONAL FERMIONS

The single impurity Kondo problem in the one-dimensional delta-potenti al Fermi gas is exactly solved for two sets of special coupling consta nts via Bethe ansatz. It is found that ferromagnetic Kondo screening d oes occur in one case which confirms the Furusaki-Nagaosa conjecture w hile in the other case it does not, which we explain in a simple physi cal picture. Exact expressions for the surface energy, the low tempera ture specific heat and the Pauli susceptibility induced by the impurit y, and the Kondo temperature are derived.