RESONANT-TUNNELING AND COULOMB OSCILLATIONS

The influence of quantum fluctuations on electron transport through sm all metallic islands with Coulomb blockade effects is studied beyond t he perturbative regime. In tunnel junctions with low resistance higher -order coherent processes and inelastic resonant tunneling become impo rtant. We present a path integral real-time description, which allows a systematic diagrammatic classification of these processes. Quantum f luctuations renormalize system parameters and lead to finite lifetime broadening. Both effects are observable in the nonlinear conductance. The finite bias voltage introduces an energy scale up to which quantum fluctuations are probed. It can be larger than the temperature, which makes quantum effects experimentally observable.