Most superconducting qubits operate in a regime dominated by either the electrical charge or the magnetic flux. Here we study an intermediate case: a hybridized charge-flux qubit with a third Josephson junction (JJ) added into the SQUID loop of the Cooper-pair box. This additional JJ allows the optimal design of a low-decoherence qubit. Both charge and flux 1/f noises are considered. Moreover, we show that an efficient quantum measurement of either the current or the charge can be achieved by using different area sizes for the third JJ.
@article{arxiv.cond-mat/0409010,
title = {Hybridized solid-state qubit in the charge-flux regime},
author = {J. Q. You and J. S. Tsai and Franco Nori},
journal= {arXiv preprint arXiv:cond-mat/0409010},
year = {2009}
}