Current noise in long diffusive SNS junctions in the incoherent multiple Andreev reflections regime - art. no. 100501

Spectral density of current fluctuations at zero frequency is calculated fo r a long diffusive SNS junction with low-resistive interfaces. At low tempe rature, T<<Delta, the subgap shot noise approaches linear voltage dependenc e, S=(2/3R)(e V+2 Delta), which is the sum of the shot noise of the normal conductor and voltage independent excess noise. This result can also be int erpreted as the 1/3-suppressed Poisson noise for the effective charge q = e (1+2 Delta /eV) transferred by incoherent multiple Andreev reflections (MAR ). At higher temperatures, anomalies of the current noise develop at the ga p subharmonics, eV=2 Delta /n. The crossover to the hot electron regime fro m the MAR regime is analyzed in the limit of small applied voltages.