The quality factor and energy decay time of superconducting resonators have been measured as a function of material, geometry, and magnetic field. Once the dissipation of trapped magnetic vortices is minimized, we identify surface two-level states (TLS) as an important decay mechanism. A wide gap between the center conductor and the ground plane, as well as use of the superconductor Re instead of Al, are shown to decrease loss. We also demonstrate that classical measurements of resonator quality factor at low excitation power are consistent with single-photon decay time measured using qubit-resonator swap experiments.
@article{arxiv.0909.0547,
title = {Improving the Coherence Time of Superconducting Coplanar Resonators},
author = {H. Wang and M. Hofheinz and J. Wenner and M. Ansmann and R. C. Bialczak and M. Lenander and Erik Lucero and M. Neeley and A. D. O'Connell and D. Sank and M. Weides and A. N. Cleland and John M. Martinis},
journal= {arXiv preprint arXiv:0909.0547},
year = {2010}
}
Comments
3 pages, 4 figures for the main paper; total 5 pages, 6 figures including supplementary material. Submitted to Applied Physics Letters