Quantitative Study of the Effect of the Environment on Macroscopic Quantum Tunneling

Data are presented on the temperature-dependent escape rates of a macroscopic system, a SQUID containing a highly damped Josephson junction, from its metastable state. These data provide the first quantitative confirmation of recent predictions of the exponential effects of temperature and damping on quantum tunneling in macroscopic systems in contrast to previously reported discrepancies. Predicted quantum corrections to thermally activated escape at high temperatures are not observed.