The Josephson quasiparticle (JQP) cycle in a voltage-biased superconducting single-electron transistor (SSET) combines coherent Cooper pair tunneling with incoherent quasiparticle decay. We have measured the influence of current flow through an independently-biased SSET on the JQP cycle when the two SSET's have a strong mutual capacitive coupling. We find, among other effects, that the JQP current in one SSET is enhanced by the presence of a quasiparticle current in the other SSET. A simplified model of the coupled-SSET system is presented which reproduces the enhancement effect.
@article{arxiv.cond-mat/9909442,
title = {Enhancement of Josephson quasiparticle current in coupled superconducting single-electron transistors},
author = {D. C. Dixon and C. P. Heij and P. Hadley and J. E. Mooij},
journal= {arXiv preprint arXiv:cond-mat/9909442},
year = {2007}
}