Published March 29, 2024 | Version Published
Journal Article Open

Achieving the Fundamental Quantum Limit of Linear Waveform Estimation

  • 1. ROR icon California Institute of Technology

Abstract

Sensing a classical signal using a linear quantum device is a pervasive application of quantum-enhanced measurement. The fundamental precision limits of linear waveform estimation, however, are not fully understood. In certain cases, there is an unexplained gap between the known waveform-estimation quantum Cramér-Rao bound and the optimal sensitivity from quadrature measurement of the outgoing mode from the device. We resolve this gap by establishing the fundamental precision limit, the waveform-estimation Holevo Cramér-Rao bound, and how to achieve it using a nonstationary measurement. We apply our results to detuned gravitational-wave interferometry to accelerate the search for postmerger remnants from binary neutron-star mergers. If we have an unequal weighting between estimating the signal’s power and phase, then we propose how to further improve the signal-to-noise ratio by a factor of 2 using this nonstationary measurement.

Copyright and License

© 2024 American Physical Society.

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PhysRevLett.132.130801.pdf

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Additional details

Identifiers

ISSN
1079-7114

Funding

Australian Research Council
CE170100004
National Science Foundation
PHY-2011968
Simons Foundation
568762
California Institute of Technology
Institute for Quantum Information and Matter
Council for Higher Education
Australian Research Council
FT210100809

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