SIMPLE FORMULATION OF THE 2-CHANNEL KONDO MODEL

We reformulate the two-channel Kondo model to explicitly remove the un scattered charge degrees of freedom. This procedure permits us to move the non-Fermi-liquid fixed point to infinite coupling where we can ap ply a perturbative strong-coupling expansion. The fixed-point Hamilton ian involves a three-body Majorana zero mode whose scattering effects give rise to marginal self-energies. The compactified model is the N = 3 member of a family of O(N) Kondo models that can be solved by semic lassical methods in the large N limit. For odd N, fermionic ''kink'' f luctuations about the N = infinity mean-field theory generate a fermio nic N-body bound state which asymptotically decouples at low energies. For N = 3, our semiclassical methods fully recover the non-Fermi-liqu id physics of the original two-channel model. Using the-same methods, we find that the corresponding O(3) Kondo lattice model develops a spi n-gap and a gapless band of coherently propagating three-body bound st ates. Its strong-coupling limit offers a rather interesting realizatio n of a marginal Fermi liquid.