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Experimental device-independent efficient certification of unsharp measurements

Wei Zhou1,*, Xinhui Li1,*,†, Ran Yang1, Linrunde Tao1, Yi-Chen Liu2, Zhenda Xie1, Yan-Xiao Gong1,3,‡, and Shi-Ning Zhu1

  • 1National Laboratory of Solid State Microstructures, School of Physics, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
  • 2Research Center for Quantum Optics and Quantum Communication, School of Science, Qingdao University of Technology, Qingdao 266525, China
  • 3Hefei National Laboratory, Hefei 230088, China

  • *These authors contributed equally to this work.
  • †Contact author: lixinhui@nju.edu.cn
  • ‡Contact author: gongyanxiao@nju.edu.cn
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Phys. Rev. Research 7, 033106 – Published 1 August, 2025

DOI: https://doi.org/10.1103/17yy-55y8

Abstract

Unsharp measurement is a unique type of measurement which provides a tradeoff between information gain and state disturbance. Such measurement is a crucial method in quantum theory and shows potential in various applications. We propose a device-independent scheme for certifying unsharp measurements with binary outcome in an efficient manner. Our scheme has low consumption of measurement resources and is robust against noise. In experiment, we demonstrate the certification of a typical kind of unsharp measurements. We achieve high fidelities above 0.9 when the strength of the unsharp measurement is less than 0.6 and get near unity fidelities in the low measurement strength range. Our scheme can be applied to enhance the feasibility and practicability of device-independent quantum information processing tasks.

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Phys. Rev. Research 7, 033106– Published 1 August, 2025
  • Received 9 September 2024
  • Revised 28 November 2024
  • Accepted 9 July 2025
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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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