Large sample-to-sample fluctuations of the nonequilibrium critical current through mesoscopic Josephson junctions

Abstract

We present a theory for the nonequilibrium current in a mesoscopic Josephson junction which is coupled to a normal electron reservoir, and apply it to a chaotic junction. Large sample-to-sample fluctuations of the critical current ${I}_{\mathrm{c}}$ are found, with rms ${I}_{\mathrm{c}}\ensuremath{\simeq}\sqrt{N}e\ensuremath{\Delta}/\ensuremath{\Elzxh},$ when the voltage difference $\mathrm{eV}$ between the electron reservoir and the junction exceeds the superconducting gap $\ensuremath{\Delta}$ and the number of modes N connecting the junction to the superconducting electrodes is large.