Effects of the phase-dependent dissipative term on the supercurrent decay of Josephson junctions

We study the decay of the zero-voltage state of an underdamped Josephson junction, including in the equivalent circuit model the interference cosφ term. From a theoretical point of view, we provide an expression for the lifetime of the metastable state, which takes into account the dependence on the voltage of both the quasiparticles tunneling and the interference-term conductances. We also present a comparison of the theory with our experimental results, which clearly indicates the importance of these intrinsic mechanisms of dissipation on the supercurrent decay. We show that the interference term must be included in the theory if agreement between theory and data is to be achieved within the experimental uncertainty.