RESONANT CONDUCTANCE-OSCILLATIONS OF A MESOSCOPIC RING IN A HIGH-FREQUENCY ELECTROMAGNETIC-FIELD

We study the influence of an ac electric field on the Aharonov-Bohm os cillations of the conductance of an ultrasmall metallic ring. The elec tric field is produced by a time-dependent component of the magnetic f lux, PHI = PHIBAR + PHI(a) cos (omegat). that threads the mesoscopic r ing. We found that resonant tunnelins through the energy levels of the ring and through their satellite levels corresponding to absorpfion o r emission of field quanta Save rise to conductance peaks. These are p eriodic in PHIBAR with period PHI0 = hc/e. For frequencies omega large compared to the energy level spacing in the ring, the main effect is a shift of the levels is-proportional-to PHI(a)2. The conductance acqu ires a quasiperiodic resonance character.