We introduce a hybrid qubit based on a semiconductor nanowire with an epitaxially grown superconductor layer. Josephson energy of the transmon-like device ("gatemon") is controlled by an electrostatic gate that depletes carriers in a semiconducting weak link region. Strong coupling to an on-chip microwave cavity and coherent qubit control via gate voltage pulses is demonstrated, yielding reasonably long relaxation times (0.8 {\mu}s) and dephasing times (1 {\mu}s), exceeding gate operation times by two orders of magnitude, in these first-generation devices. Because qubit control relies on voltages rather than fluxes, dissipation in resistive control lines is reduced, screening reduces crosstalk, and the absence of flux control allows operation in a magnetic field, relevant for topological quantum information.
@article{arxiv.1503.08339,
title = {A Semiconductor Nanowire-Based Superconducting Qubit},
author = {T. W. Larsen and K. D. Petersson and F. Kuemmeth and T. S. Jespersen and P. Krogstrup and J. Nygard and C. M. Marcus},
journal= {arXiv preprint arXiv:1503.08339},
year = {2015}
}