Fractional quantum Hall junctions and two-channel Kondo models - art. no. 235301

A mapping between fractional quantum Hall (FQH) junctions and the two-chann el Kondo model is presented. We discuss this relation in detail for the par ticular case of a junction of a FQH state at nu= 1/3 and a normal metal. We show that in the strong coupling regime this junction has a non-Fermi-liqu id fixed point. At this fixed point the electron Green's function has a bra nch cut and the impurity entropy is equal to S = 1/2 In 2. We construct the space of perturbations at the strong coupling fixed point and find that th e dimension of the tunneling operator is 1/2. These properties are strongly reminiscent of the non-Fermi-liquid fixed points of a number of quantum im purity models, particularly the two-channel Kondo model. However we have fo und that, in spite of these similarities, the Hilbert spaces of these two s ystems are quite different. In particular, although in a special limit the Hamiltonians of both systems are the same, their Hilbert spaces are not Sin ce they are determined by physically distinct boundary conditions. As a con sequence the spectrum of operators in the two problems is different.