arXiv subjects
Publications and source records attributed to Yasuyuki Kayama.
We introduce an integrable impurity model in which both electrons and impurity have spin and flavour degrees of freedom. This model is a generalization of the multi-channel Kondo model and closely related with resonant tunneling through quantum dot. The Hamiltonian is exactly diagonalized by means of the Bethe ansatz.
Low-energy excitations in spin 1/2 antiferromagnetic Heisenberg spin ladders are studied by bosonization and gauge theoretical description. It is explicitly shown that zero modes in the bosonization play an essentially important role. Low-energy excitations in the 2-leg system is described by spin triplet Majorana fermions, and in the 3-leg case spin excitations on the top and bottom ladders are described by two massless scalar fields. It is predicted that if inter-ladder interaction between the top and bottom chains is introduced, a phase transition occures at some critical coupling and the system acquires an energy gap.