Thermodynamics of the anisotropic two-channel Kondo problem

We construct and solve numerically the thermodynamic Bethe Ansatz equations for the spin-anisotropic two-channel Kondo model in arbitrary external field h . At high temperatures the specific heat and the susceptibility show power law dependence. For h → 0 and at temperatures below the Kondo temperature T K a two-channel Kondo effect develops characterized by a Wilson ratio 8 / 3, and a logarithmic divergence of the susceptibility and the linear specific heat coefficient. Finite magnetic field, h > 0 drives the system to a Fermi liquid fixed point with an unusual Wilson ratio which depends sensitively on h .