Nonlocal transport mediated by nonlocal Hikami boxes: Condensation of evanescent quasiparticles injected into the superconducting gap

Abstract

Evanescent quasiparticles entering a superconductor and propagating over distances larger than the coherence length give rise to intermediate states induced by double Andreev scattering on disorder.The resulting effective attractive interaction between evanescent quasiparticles is retarded at the extremely slow frequency of the applied bias voltage. The non-BCS out-of-equilibrium mesoscopic condensate is compatible with a recent experiment [S. Russo et al., Phys. Rev. Lett. 95, 027002 (2005)]. Microscopic theory is discussed in the random phase approximation.