We examine the possibility of macroscopic fluctuations in the electrical resistance R of a disordered mesoscopic superconductor. A perturbative argument shows that in the presence of phase fluctuations, quantum interference can cause the Andreev scattering amplitude to vanish, leading to a 1/${\mathit{R}}^2$ tail in the probability distribution for R. Consequently no moments exist and the boundary resistance exhibits large fluctuations. This prediction is confirmed by numerical simulations on superconducting loops, connected to external reservoirs by point contacts.

• Received 21 June 1993

DOI:https://doi.org/10.1103/PhysRevB.48.10391