We realize indirect partial measurement of a transmon qubit in circuit quantum electrodynamics by interaction with an ancilla qubit and projective ancilla measurement with a dedicated readout resonator. Accurate control of the interaction and ancilla measurement basis allows tailoring the measurement strength and operator. The tradeoff between measurement strength and qubit back-action is characterized through the distortion of a qubit Rabi oscillation imposed by ancilla measurement in different bases. Combining partial and projective qubit measurements, we provide the solid-state demonstration of the correspondence between a non-classical weak value and the violation of a Leggett-Garg inequality.
@article{arxiv.1302.5147,
title = {Partial-measurement back-action and non-classical weak values in a superconducting circuit},
author = {J. P. Groen and D. Ristè and L. Tornberg and J. Cramer and P. C. de Groot and T. Picot and G. Johansson and L. DiCarlo},
journal= {arXiv preprint arXiv:1302.5147},
year = {2013}
}
Comments
5 pages, 4 figures, and Supplementary Information (8 figures)