Influence of a weak inhomogeneity of a tunnel barrier on localized states induced by superconducting current in a Josephson (SIS) junction

A theory is formulated to account for the influence of random structural inhomogeneities of a tunnel barrier on localized states induced by a superconducting current in Josephson junctions. A general equation for a quasidiscrete level is derived on the assumption that the fluctuations of the barrier potential are small. It is shown that the decrease in energy of the localized level and its attenuation are attributable to the finite probability of tunneling without conservation of the momentum component parallel to the barrier.