We demonstrate feedback control of a superconducting transmon qubit using discrete, projective measurement and conditional coherent driving. Feedback realizes a fast and deterministic qubit reset to a target state with 2.4% error averaged over input superposition states, and cooling of the transmon from 16% spurious excitation to 3%. This closed-loop qubit control is necessary for measurement-based protocols such as quantum error correction and teleportation.
@article{arxiv.1207.2944,
title = {Feedback control of a solid-state qubit using high-fidelity projective measurement},
author = {D. Ristè and C. C. Bultink and K. W. Lehnert and L. DiCarlo},
journal= {arXiv preprint arXiv:1207.2944},
year = {2012}
}
Comments
5 pages, 4 figures, and Supplementary Information (5 figures)