Thermal activation and macroscopic quantum phenomena in superconducting devices

This thesis is a study of escape from metastable wells in one and two dimensional potentials of superconducting devices. We have measured escape rates due to both thermal activation over the barrier and macroscopic quantum tunneling through the barrier. The measurements were performed for a variety of device parameters, corresponding to different shapes of the potential barrier. We find strong evidence for macroscopic quantum tunneling in both one and two dimensional systems with an escape rate that is very sensitive to the dissipation present in the system. Surprisingly, we have also found a discrepancy between our results and the predictions of Kramers' thermal activation model in certain types of potentials.U of I OnlyETDs are only available to UIUC Users without author permissio