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  • Open Access

Private Remote Phase Estimation over a Lossy Quantum Channel

Farzad Kianvash1, Marco Barbieri2,3,4, and Matteo Rosati1

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Phys. Rev. Lett. 136, 060805 – Published 11 February, 2026

DOI: https://doi.org/10.1103/rhgw-t21z

Abstract

Private remote quantum sensing aims at estimating a parameter at a distant location by transmitting quantum states on an insecure quantum channel, limiting information leakage and disruption of the estimation itself from an adversary. Previous results highlighted that one can bound the estimation performance in terms of the observed noise. However, if no assumptions are placed on the channel model, such bounds are very loose and severely limit the estimation. We propose and analyze a private remote sensing protocol using—for the first time, to our knowledge—continuous-variable states in the single-user setting. Assuming a typical class of lossy attacks and employing tools from quantum communication, we calculate the true estimation error and privacy of our protocol, both in the asymptotic limit of many channel uses and in the finite-size regime. Our results show that a realistic channel-model assumption, which can be validated with measurement data, allows for a much tighter quantification of the estimation error and privacy for all practical purposes.

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Phys. Rev. Lett. 136, 060805– Published 11 February, 2026
  • Received 12 November 2025
  • Accepted 21 January 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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