RESONANT MACROSCOPIC QUANTUM TUNNELING IN SQUID SYSTEMS

A detailed theoretical analysis of the resonant macroscopic quantum tu nneling in superconducting quantum interference device systems is pres ented. Our approach allows us to include the effect of both temperatur e and sweeping rate of the external flux, and to study the phenomenon both in quasistationary and nonstationary conditions, which can be ind uced by a fast sweep of the external bias. Moreover we compare our the ory with the experimental data of Rouse, Han, and Lukens [Phys. Rev. L ett. 75, 1614 (1995)] referring to the quasi-stationary case, while ot her observable effects are predicted in the nonstationary case.