A detailed analysis was made of all of the possible fixed points of the effective Hamiltonian of a non-magnetic impurity which hopped between 2 sites in a metal. A line of non-Fermi liquid fixed points was found which continuously interpolated between the 2-channel Kondo fixed point and the 1-channel, 2-impurity Kondo fixed point. There was one relevant direction with scaling dimension, and one leading irrelevant operator with dimension 3/2. There was also one marginal operator in the spin sector moving along this line. The marginal operator, when combined with the leading irrelevant operator, generated the relevant operator. The system was shown to flow to a line of Fermi-liquid fixed points which continuously interpolated between the non-interacting fixed point and the 2-channel spin-flavor Kondo fixed point.

Solution of the Effective Hamiltonian of Impurity Hopping between Two Sites in a Metal J.Ye: Physical Review B, 1997, 56[3], 1316-34