Photoinduced Macroscopic Quantum Tunneling in Superconducting Interference Devices

Abstract

It is shown that a time-varying magnetic field through the superconducting loop in a rf SQUID can cause transitions between the fluxoid states. Experimental observation of these transitions should constitute evidence for the quantum mechanical character of the macroscopic variable, the total flux through the loop. In the case that dissipation is characterized by linear damping in the quasiclassical limit, the photon absorption process depends critically on the ratio of the resistance of the weak link to the fundamental unit of resistance $\frac{h}{e^2}$.