QUASI-ENERGY SPECTROSCOPY IN MESOSCOPIC SYSTEMS

Small ac-driven Josephson junctions and related problems are studied in the quantum regime, in the framework of a simple model. In such time-dependent problems, the quasienergies play a role similar to the role of energies in time-independent problems. These are calculated, both numerically and analytically in perturbation theory. A spectroscopic method for measuring the quasienergy differences is suggested. The quasienergy states are found to be localized in energy. Experimental measurement of quasienergy differences will provide strong support for quantum coherence of mesoscopic systems, as discussed in this work.