We determine the quasi-particle excitation spectrum in the normal region of a narrow ballistic superconductor--normal-metal--superconductor (SNS) Josephson contact. Increasing the effective chemical potential in the contact converts the electronic levels into Andreev-levels carrying supercurrent. The opening of these superchannels leads to a supercurrent quantization which exhibits a non-universal behavior in general and we discuss its dependence on the junction parameters.
@article{arxiv.cond-mat/9907460,
title = {Supercurrent Quantization in Narrow Channel SNS Junctions},
author = {Nikolai M. Chtchelkatchev and Gordey B. Lesovik and Gianni Blatter},
journal= {arXiv preprint arXiv:cond-mat/9907460},
year = {2007}
}