QUANTUM BROWNIAN-MOTION IN A PERIODIC POTENTIAL AND THE MULTICHANNEL KONDO PROBLEM

We study the motion of a particle in a periodic potential with Ohmic d issipation. In D=1 dimension it is well known that there are two phase s depending on the dissipation: a localized phase with zero temperatur e mobility mu=0 and a fully coherent phase with mu unaffected by the p eriodic potential. However, for nonsymmorphic lattices with D>1, such as the honeycomb lattice, there is an intermediate phase with a univer sal mobility mu. This intermediate phase is relevant to resonant tunn eling experiments in strongly coupled Coulomb-blockade structures as w ell as multichannel Luttinger liquids. We relate this problem to the T oulouse limit of the D + 1 channel Kondo problem, which allows us to c ompute mu exactly using results known from conformal field theory.