Effect of dissipation on thermal activation in an underdamped Josephson junction: First evidence of a transition between different damping regimes

Measurements of the lifetime of the zero-voltage state in a single hysteretic Josephson junction show clear evidence of two different damping regimes. Results are obtained for a wide range of damping within the underdamped region because the damping resistance depends exponentially on inverse temperature as does the junction's quasiparticle resistance. Thus a further insight is also given on the thorny problem of the damping resistance for the resistively shunted junction model.