We present a new readout method for a superconducting flux qubit, based on the measurement of the Josephson inductance of a superconducting quantum interference device that is inductively coupled to the qubit. The intrinsic flux detection efficiency and back-action are suitable for a fast and nondestructive determination of the quantum state of the qubit, as needed for readout of multiple qubits in a quantum computer. We performed spectroscopy of a flux qubit and we measured relaxation times of the order of 80 μs.
@article{arxiv.cond-mat/0311510,
title = {Nondestructive readout for a superconducting flux qubit},
author = {A. Lupascu and C. J. M. Verwijs and R. N. Schouten and C. J. P. M. Harmans and J. E. Mooij},
journal= {arXiv preprint arXiv:cond-mat/0311510},
year = {2007}
}
Comments
4 pages, 4 figures; modified content, figures and references; accepted for publication in Phys. Rev. Lett