Quantum Advantage for Sensing Properties of Classical Fields
Abstract
Modern precision experiments often probe unknown classical fields with bosonic sensors in quantum-noise-limited regimes where vacuum fluctuations limit conventional readout. We introduce quantum signal learning, a sensing framework that extends metrology to a broader property-learning setting, and propose a quantum-enhanced protocol that simultaneously estimates many properties of a classical signal with shot noise suppressed below the vacuum level. Our scheme requires only two-mode squeezing, passive optics, and static homodyne measurements, and enables post hoc classical estimation of many properties from the same experimental dataset. We prove that our protocol enables a quantum speedup for common classical sensing tasks, including measuring electromagnetic correlations, real-time feedback control of interferometric cavities, and Fourier-domain matched filtering. To establish these separations, we introduce an optimal-transport conditioning method and show both worst-case exponential separations from all entanglement-free strategies and practical speedups over homodyne and heterodyne baselines. We further show that when squeezing is treated as a resource, a protocol with squeezed light can sense a structured classical background exponentially faster than any coherent classical probe.
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BibTeX
@article{cotler2026quantum,
title = {{Quantum Advantage for Sensing Properties of Classical Fields}},
author = {Jordan Cotler and Daine L. Danielson and Ishaan Kannan},
journal = {Physical Review X},
year = {2026},
month = oct,
doi = {10.1103/6ps1-mw9l},
url = {http://link.aps.org/doi/10.1103/6ps1-mw9l},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Quantum Advantage for Sensing Properties of Classical Fields
AU - Jordan Cotler
AU - Daine L. Danielson
AU - Ishaan Kannan
PY - 2026
DA - 2026/10/23
JO - Physical Review X
DO - 10.1103/6ps1-mw9l
UR - http://link.aps.org/doi/10.1103/6ps1-mw9l
AB - Modern precision experiments often probe unknown classical fields with bosonic sensors in quantum-noise-limited regimes where vacuum fluctuations limit conventional readout. We introduce quantum signal learning, a sensing framework that extends metrology to a broader property-learning setting, and propose a quantum-enhanced protocol that simultaneously estimates many properties of a classical signal with shot noise suppressed below the vacuum level. Our scheme requires only two-mode squeezing, passive optics, and static homodyne measurements, and enables post hoc classical estimation of many properties from the same experimental dataset. We prove that our protocol enables a quantum speedup for common classical sensing tasks, including measuring electromagnetic correlations, real-time feedback control of interferometric cavities, and Fourier-domain matched filtering. To establish these separations, we introduce an optimal-transport conditioning method and show both worst-case exponential separations from all entanglement-free strategies and practical speedups over homodyne and heterodyne baselines. We further show that when squeezing is treated as a resource, a protocol with squeezed light can sense a structured classical background exponentially faster than any coherent classical probe.
SN - 2160-3308
ER -