Experimental demonstration of non-bilocality with truly independent sources and strict locality constraints

Nature Photonics volume 13, pages687–691(2019)Cite this article

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Abstract

The ongoing interest in creating a secure global quantum network culminated recently in the demonstration of transcontinental quantum communication1. There is a pressing need to examine the properties attached to a quantum network architecture from multiple perspectives, including physics foundations2, communication security3, the efficient use of resources and innovative technological applications4,5. Here, we present an experimental realization of a five-node quantum network, in which quantum sources at two nodes deliver entangled photon pairs to three measurement nodes. With relevant events between five nodes separated space-like, we demonstrate violation of the Bell inequality and bilocal inequality6, with the locality, measurement independence and quantum source independence loopholes closed simultaneously in a quantum network. This experimental realization may be valuable for the design and implementation of future quantum networks.

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Fig. 1: Space–time diagram of the simplest quantum network.
Fig. 2: Schematics for testing the bilocality in a network.
Fig. 3: Space–time configuration of relevant events in each experimental trial.
Fig. 4: \({\cal{B}}_{13}\) and \(\cal{S}\) versus noise parameter p.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

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Acknowledgements

We thank Y. Liu, Y. Li and Y.-Q. Nie for enlightening discussions, Y.-L. Mao for assistance, K.-X. Yang for help with the aerial photographs and Quantum Ctek for providing the components used in the QRNGs. This work was supported by the National Key R&D Program of China (2017YFA0303900, 2017YFA0304000), the National Natural Science Foundation of China and the Chinese Academy of Sciences.

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Author notes

  1. These authors contributed equally: Qi-Chao Sun, Yang-Fan Jiang, Bing Bai.

Affiliations

  1. National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, Shanghai Branch, University of Science and Technology of China, Shanghai, China
    • Qi-Chao Sun
    • , Yang-Fan Jiang
    • , Bing Bai
    • , Xiao Jiang
    • , Jun Zhang
    • , Qiang Zhang
    • , Jingyun Fan
    •  & Jian-Wei Pan
  2. CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, Shanghai Branch, University of Science and Technology of China, Shanghai, China
    • Qi-Chao Sun
    • , Yang-Fan Jiang
    • , Bing Bai
    • , Xiao Jiang
    • , Jun Zhang
    • , Qiang Zhang
    • , Jingyun Fan
    •  & Jian-Wei Pan
  3. State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, China
    • Weijun Zhang
    • , Hao Li
    • , Lixing You
    •  & Zhen Wang
  4. Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
    • Xianfeng Chen
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Contributions

Q.-C.S., Q.Z., J.F. and J.-W.P. conceived and designed the experiments. B.B. and J.Z. built the QRNGs. W.Z., H.L., L.Y. and Z.W. fabricated the SNSPDs. Q.-C.S. and Y.-F.J. built the experimental network and carried out the experiment. X.J. and X.C. provided experimental assistance. Q.-C.S. and Y.-F.J. analysed the data. Q.-C.S., Q.Z., J.F. and J.-W.P. wrote the manuscript, with input from all authors.

Corresponding authors

Correspondence to Qiang Zhang or Jingyun Fan or Jian-Wei Pan.

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Sun, Q., Jiang, Y., Bai, B. et al. Experimental demonstration of non-bilocality with truly independent sources and strict locality constraints. Nat. Photonics 13, 687–691 (2019). https://doi.org/10.1038/s41566-019-0502-7

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