Improved Superconducting Qubit Readout by Qubit-Induced Nonlinearities

Maxime Boissonneault, J. M. Gambetta, and Alexandre Blais

Phys. Rev. Lett. 105, 100504 – Published 2 September 2010

Abstract

In dispersive readout schemes, qubit-induced nonlinearity typically limits the measurement fidelity by reducing the signal-to-noise ratio (SNR) when the measurement power is increased. Contrary to seeing the nonlinearity as a problem, here we propose to use it to our advantage in a regime where it can increase the SNR. We show analytically that such a regime exists if the qubit has a many-level structure. We also show how this physics can account for the high-fidelity avalanchelike measurement recently reported by Reed et al. [arXiv:1004.4323v1].

Received 30 April 2010

DOI:https://doi.org/10.1103/PhysRevLett.105.100504

Authors & Affiliations

Maxime Boissonneault¹, J. M. Gambetta², and Alexandre Blais¹

¹Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada, J1K 2R1
²Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada

Response of the Strongly Driven Jaynes-Cummings Oscillator

Lev S. Bishop, Eran Ginossar, and S. M. Girvin

Phys. Rev. Lett. 105, 100505 (2010)

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Vol. 105, Iss. 10 — 3 September 2010

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