We have studied the transition rate from metastable wells in the two-dimensional potential of a dc SQUID as a function of applied flux and temperature. We observe a crossover from thermally activated escape to macroscopic quantum tunneling at a flux-dependent temperature. The thermal rates are significantly suppressed, suggesting that the potential barrier for activation is effectively enhanced by the interaction of the macroscopic degrees of freedom in the device.
ASJC Scopus subject areas
- Physics and Astronomy(all)