中国物理B ›› 2020, Vol. 29 ›› Issue (8): 80301-080301.doi: 10.1088/1674-1056/ab9288

• SPECIAL TOPIC—Ultracold atom and its application in precision measurement • 上一篇    下一篇

Detection and quantification of entanglement with measurement-device-independent and universal entanglement witness

Zhi-Jin Ke(柯芝锦), Yi-Tao Wang(王轶韬), Shang Yu(俞上), Wei Liu(刘伟), Yu Meng(孟雨), Zhi-Peng Li(李志鹏), Hang Wang(汪航), Qiang Li(李强), Jin-Shi Xu(许金时), Ya Xiao(肖芽), Jian-Shun Tang(唐建顺), Chuan-Feng Li(李传锋), Guang-Can Guo(郭光灿)   

  1. 1 CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    3 Department of Physics, Ocean University of China, Qingdao 266100, China
  • 收稿日期:2020-01-15 修回日期:2020-04-22 出版日期:2020-08-05 发布日期:2020-08-05
  • 通讯作者: Jian-Shun Tang, Chuan-Feng Li E-mail:tjs@ustc.edu.cn;cfli@ustc.edu.cn
  • 基金资助:

    Project supported by the National Key Research and Development Program of China (Grant No. 2016YFA0302700), the National Natural Science Foundation of China (Grant Nos. 11674304, 11822408, 11774335, 61490711, 11474267, 11821404, and 91321313), the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2017492), the Foundation for Scientific Instrument and Equipment Development of Chinese Academy of Sciences (Grant No. YJKYYQ20170032), the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant No. QYZDY-SSW-SLH003), and the Fundamental Research Funds for the Central Universities, China (Grant No. WK2470000026).

Detection and quantification of entanglement with measurement-device-independent and universal entanglement witness

Zhi-Jin Ke(柯芝锦)1,2, Yi-Tao Wang(王轶韬)1,2, Shang Yu(俞上)1,2, Wei Liu(刘伟)1,2, Yu Meng(孟雨)1,2, Zhi-Peng Li(李志鹏)1,2, Hang Wang(汪航)1,2, Qiang Li(李强)1,2, Jin-Shi Xu(许金时)1,2, Ya Xiao(肖芽)3, Jian-Shun Tang(唐建顺)1,2, Chuan-Feng Li(李传锋)1,2, Guang-Can Guo(郭光灿)1,2   

  1. 1 CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    3 Department of Physics, Ocean University of China, Qingdao 266100, China
  • Received:2020-01-15 Revised:2020-04-22 Online:2020-08-05 Published:2020-08-05
  • Contact: Jian-Shun Tang, Chuan-Feng Li E-mail:tjs@ustc.edu.cn;cfli@ustc.edu.cn
  • Supported by:

    Project supported by the National Key Research and Development Program of China (Grant No. 2016YFA0302700), the National Natural Science Foundation of China (Grant Nos. 11674304, 11822408, 11774335, 61490711, 11474267, 11821404, and 91321313), the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2017492), the Foundation for Scientific Instrument and Equipment Development of Chinese Academy of Sciences (Grant No. YJKYYQ20170032), the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant No. QYZDY-SSW-SLH003), and the Fundamental Research Funds for the Central Universities, China (Grant No. WK2470000026).

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摘要：

Entanglement is the key resource in quantum information processing, and an entanglement witness (EW) is designed to detect whether a quantum system has any entanglement. However, prior knowledge of the target states should be known first to design a suitable EW, which weakens this method. Nevertheless, a recent theory shows that it is possible to design a universal entanglement witness (UEW) to detect negative-partial-transpose (NPT) entanglement in unknown bipartite states with measurement-device-independent (MDI) characteristic. The outcome of a UEW can also be upgraded to be an entanglement measure. In this study, we experimentally design and realize an MDI UEW for two-qubit entangled states. All of the tested states are well-detected without any prior knowledge. We also show that it is able to quantify entanglement by comparing it with concurrence estimated through state tomography. The relation between them is also revealed. The entire experimental framework ensures that the UEW is MDI.

关键词: entanglement witness, entanglement detection, entanglement quantification, measurement-device-independent

Abstract:

Entanglement is the key resource in quantum information processing, and an entanglement witness (EW) is designed to detect whether a quantum system has any entanglement. However, prior knowledge of the target states should be known first to design a suitable EW, which weakens this method. Nevertheless, a recent theory shows that it is possible to design a universal entanglement witness (UEW) to detect negative-partial-transpose (NPT) entanglement in unknown bipartite states with measurement-device-independent (MDI) characteristic. The outcome of a UEW can also be upgraded to be an entanglement measure. In this study, we experimentally design and realize an MDI UEW for two-qubit entangled states. All of the tested states are well-detected without any prior knowledge. We also show that it is able to quantify entanglement by comparing it with concurrence estimated through state tomography. The relation between them is also revealed. The entire experimental framework ensures that the UEW is MDI.

Key words: entanglement witness, entanglement detection, entanglement quantification, measurement-device-independent

中图分类号:  (Quantum information)

  • 03.67.-a
03.67.Mn (Entanglement measures, witnesses, and other characterizations) 42.50.Ex (Optical implementations of quantum information processing and transfer)