Effect of random quantum jumpers on the single-particle low-temperature current in dirty SIN junctions

A formula has been obtained for a single-particle current in “dirty” (low concentrations of identical nonmagnetic impurities in the I layer) SIN junctions (S is a superconductor, I is an insulator, N is a normal metal) at low temperatures $0 \leqslant T \ll \Delta_{0}^{}$ and voltages $0 \leqslant |eV| < \Delta_{0}^{}$, where $\Delta_{0}^{}$ is the superconducting gap in the S shore at $T = 0$, $V$ is the voltage across the junction, and $e$ is the elementary charge. It has been shown that the presence of random narrowband quantum jumpers in the dirty SIN junction results in a significant lowering of single-particle current-voltage characteristics of the SIN junction compared to single-particle current-voltage characteristics calculated for the same junction within the existing theory. This behavior can be used as an experimental criterion of the presence of such jumpers in the junction. Numerical estimates indicating the possibility of the experimental manifestation of this effect have been presented. The scheme of the experiment for the detection of this effect has been proposed.