中国物理B ›› 2021, Vol. 30 ›› Issue (9): 90304-090304.doi: 10.1088/1674-1056/ac0bae

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Quantum metrology with coherent superposition of two different coded channels

Dong Xie(谢东)1,†, Chunling Xu(徐春玲)1, and Anmin Wang(王安民)2   

  1. 1 College of Science, Guilin University of Aerospace Technology, Guilin 541004, China;
    2 Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
  • 收稿日期:2021-04-14 修回日期:2021-05-23 接受日期:2021-06-16 出版日期:2021-08-19 发布日期:2021-08-30
  • 通讯作者: Dong Xie E-mail:xiedong@mail.ustc.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 62001134), the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2020GXNSFAA159047), and the National Key Research and Development Program of China (Grant No. 2018YFB1601402-2).

Quantum metrology with coherent superposition of two different coded channels

Dong Xie(谢东)1,†, Chunling Xu(徐春玲)1, and Anmin Wang(王安民)2   

  1. 1 College of Science, Guilin University of Aerospace Technology, Guilin 541004, China;
    2 Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
  • Received:2021-04-14 Revised:2021-05-23 Accepted:2021-06-16 Online:2021-08-19 Published:2021-08-30
  • Contact: Dong Xie E-mail:xiedong@mail.ustc.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 62001134), the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2020GXNSFAA159047), and the National Key Research and Development Program of China (Grant No. 2018YFB1601402-2).

摘要: We investigate the advantage of coherent superposition of two different coded channels in quantum metrology. In a continuous variable system, we show that the Heisenberg limit 1/N can be beaten by the coherent superposition without the help of indefinite causal order. And in parameter estimation, we demonstrate that the strategy with the coherent superposition can perform better than the strategy with quantum switch which can generate indefinite causal order. We analytically obtain the general form of estimation precision in terms of the quantum Fisher information and further prove that the nonlinear Hamiltonian can improve the estimation precision and make the measurement uncertainty scale as 1/Nm for m≥2. Our results can help to construct a high-precision measurement equipment, which can be applied to the detection of coupling strength and the test of time dilation and the modification of the canonical commutation relation.

关键词: quantum metrology, quantum switch, quantum Fisher information, coherent superposition

Abstract: We investigate the advantage of coherent superposition of two different coded channels in quantum metrology. In a continuous variable system, we show that the Heisenberg limit 1/N can be beaten by the coherent superposition without the help of indefinite causal order. And in parameter estimation, we demonstrate that the strategy with the coherent superposition can perform better than the strategy with quantum switch which can generate indefinite causal order. We analytically obtain the general form of estimation precision in terms of the quantum Fisher information and further prove that the nonlinear Hamiltonian can improve the estimation precision and make the measurement uncertainty scale as 1/Nm for m≥2. Our results can help to construct a high-precision measurement equipment, which can be applied to the detection of coupling strength and the test of time dilation and the modification of the canonical commutation relation.

Key words: quantum metrology, quantum switch, quantum Fisher information, coherent superposition

中图分类号:  (Quantum information)

  • 03.67.-a
06.20.-f (Metrology) 03.65.Aa (Quantum systems with finite Hilbert space) 03.65.-w (Quantum mechanics)