Journal article
Homodyne measurement with a Schrödinger cat state as a local oscillator
J Combes, AP Lund
Physical Review A | AMER PHYSICAL SOC | Published : 2022
Abstract
Homodyne measurements are a widely used quantum measurement. Using a coherent state of large amplitude as the local oscillator, it can be shown that the quantum homodyne measurement limits to a field quadrature measurement. In this work, we give an example of a general idea: injecting nonclassical states as a local oscillator can lead to nonclassical measurements. Specifically, we consider injecting a superposition of coherent states, a Schrödinger cat state, as a local oscillator. We derive the Kraus operators and the positive operator-valued measure in this situation.
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Awarded by Bundesministerium für Bildung und Forschung
Funding Acknowledgements
The authors thank Ben Baragiola, Anita Dabrowska, Mac Kim, Noah Lordi, Nicolas Menicucci, and Eugene Tsao for helpful discussions. We would also like to thank both anonymous referees for helping us to clarify and improve the paper. J.C. was funded in part by the Australian Research Council through the Discovery Early Career Research Award (DECRA) Project No. DE160100356, the National Science Foundation QLCI Award No. OMA-2016244, and the Office of Naval Research Award No. N00014-22-1-2438. A.P.L. acknowledges support from BMBF (QPIC) and the Einstein Research Unit on Quantum Devices. This research was supported by the Australian Research Council (ARC) under the Centre of Excellence for Quantum Computation and Communication Technology (Project No. CE170100012).