中国物理B ›› 2025, Vol. 34 ›› Issue (7): 70303-070303.doi: 10.1088/1674-1056/adc7ee

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Quantum-enhanced time-of-arrival measuring method based on partially entangled state

Peng-Xian Li(李芃鲜)1, Lu-Ping Xu(许录平)1,†, Gui-Ting Hu(胡桂廷)1, and Wen-Long Gao(高文珑)2   

  1. 1 School of Aerospace Science and Technology, Xidian University, Xi'an 710126, China;
    2 Electronic Engineering Research Institute, Xi'an 710100, China
  • 收稿日期:2025-01-14 修回日期:2025-03-24 接受日期:2025-04-02 出版日期:2025-06-18 发布日期:2025-07-07
  • 通讯作者: Lu-Ping Xu E-mail:Lpxu@mail.xidian.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 62071363) and the Key Research and Development Projects of Shaanxi Province, China (Grant No. 2021LLRH-06).

Quantum-enhanced time-of-arrival measuring method based on partially entangled state

Peng-Xian Li(李芃鲜)1, Lu-Ping Xu(许录平)1,†, Gui-Ting Hu(胡桂廷)1, and Wen-Long Gao(高文珑)2   

  1. 1 School of Aerospace Science and Technology, Xidian University, Xi'an 710126, China;
    2 Electronic Engineering Research Institute, Xi'an 710100, China
  • Received:2025-01-14 Revised:2025-03-24 Accepted:2025-04-02 Online:2025-06-18 Published:2025-07-07
  • Contact: Lu-Ping Xu E-mail:Lpxu@mail.xidian.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 62071363) and the Key Research and Development Projects of Shaanxi Province, China (Grant No. 2021LLRH-06).

摘要: We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequency-entangled states. By establishing the fundamental relationship between the degree of entanglement, channel transmission efficiency and measurement precision, we demonstrate superclassical timing resolution in both lossless and lossy regimes. Theoretical analysis and numerical simulations reveal that, under a lossless channel, the precision gain increases with the degree of entanglement, approaching the Heisenberg limit. Importantly, in lossy channels, the precision gain is significantly influenced by both the channel transmission efficiency and the degree of entanglement. For transmission efficiencies above 50%, the proposed method provides up to 1.5 times the precision gain of classical methods when entanglement parameters are optimized. Moreover, by optimizing intra-group and inter-group covariances in the multi-structured entangled state, we achieve substantial precision gains even at low transmission efficiencies ($\sim 30%$), demonstrating its robustness against loss. This study resolves the critical trade-off between entanglement-enhanced precision and loss-induced information degradation. Future implementation could extend to satellite-based quantum positioning, remote sensing, quantum illumination, and other fields that require high-precision ranging in lossy environments. The protocol establishes a universal framework for loss-tolerant quantum metrology, advancing the practical deployment of quantum-enhanced sensing in real-world applications.

关键词: quantum ranging, partially entangled state, degree of entanglement

Abstract: We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequency-entangled states. By establishing the fundamental relationship between the degree of entanglement, channel transmission efficiency and measurement precision, we demonstrate superclassical timing resolution in both lossless and lossy regimes. Theoretical analysis and numerical simulations reveal that, under a lossless channel, the precision gain increases with the degree of entanglement, approaching the Heisenberg limit. Importantly, in lossy channels, the precision gain is significantly influenced by both the channel transmission efficiency and the degree of entanglement. For transmission efficiencies above 50%, the proposed method provides up to 1.5 times the precision gain of classical methods when entanglement parameters are optimized. Moreover, by optimizing intra-group and inter-group covariances in the multi-structured entangled state, we achieve substantial precision gains even at low transmission efficiencies ($\sim 30%$), demonstrating its robustness against loss. This study resolves the critical trade-off between entanglement-enhanced precision and loss-induced information degradation. Future implementation could extend to satellite-based quantum positioning, remote sensing, quantum illumination, and other fields that require high-precision ranging in lossy environments. The protocol establishes a universal framework for loss-tolerant quantum metrology, advancing the practical deployment of quantum-enhanced sensing in real-world applications.

Key words: quantum ranging, partially entangled state, degree of entanglement

中图分类号:  (Quantum information)

  • 03.67.-a
42.50.-p (Quantum optics) 42.50.Dv (Quantum state engineering and measurements) 42.50.Ex (Optical implementations of quantum information processing and transfer)