Charging-energy corrections to macroscopic quantum tunneling in small Josephson junctions.

Abstract

We study the effect of the phase dependence of the effective capacitance of Josephson junctions on macroscopic quantum tunneling. We calculate the correction due to the nonlinearity of the capacitance on the rate of escape out of a metastable well, in the presence of Ohmic dissipation, and discuss its dependence on the parameters of the junction. We show that the correction tends to enhance the escape rate and that the enhancement becomes more pronounced as the self-capacitance or the normal-state resistance of the junction is reduced.