We introduce a three-junction SQUID that can be effectively used as an optimal tunable element in Josephson quantum computing applications. This device can replace the simple dc SQUID generally used as tunable element in this kind of applications, with a series of advantages for the coherence time and for the tolerance to small errors. We study the device both theoretically and experimentally at 4.2 K, obtaining a good agreement between the results.
@article{arxiv.0805.0979,
title = {An Optimal Tunable Josephson Element for Quantum Computing},
author = {F. Chiarello and M. G. Castellano and G. Torrioli and S. Poletto and C. Cosmelli and P. Carelli and D. V. Balashov and M. I. Khabipov and A. B. Zorin},
journal= {arXiv preprint arXiv:0805.0979},
year = {2009}
}