THERMAL-ACTIVATION ABOVE A DISSIPATION BARRIER - SWITCHING OF A SMALLJOSEPHSON-JUNCTION

An unshunted Josephson tunnel junction switching out of its zero-volta ge state is a model system for thermal activation out of a metastable state. For small-capacitance low-critical-current junctions; this ther mal activation process follows a generalized Arrhenius law involving d issipation directly in its exponent. I This escape over a dissipation barrier can be computed exactly for a junction connected to a RC imped ance providing large damping. The diffusion branch and the switching h istograms measured for such a junction are in agreement with theory.