Abstract

Quantum memory networks as an intermediate stage in the development of a quantum internet1 will enable a number of significant applications2,3,4,5. To connect and entangle remote quantum memories, it is best to use photons. In previous experiments6,7,8,9,10,11,12,13, entanglement of two memory nodes has been achieved via photon interference. Going beyond the state of the art by entangling many quantum nodes at a distance is highly sought after. Here, we report the entanglement of three remote quantum memories via three-photon interference. We employ laser-cooled atomic ensembles and make use of a ring cavity to enhance the overall efficiency of our memory–photon entanglement. By interfering three single photons from three separate set-ups, we create entanglement of three memories and three photons. Then, by measuring the photons and applying feed-forward, we achieve heralded entanglement between the three memories. Our experiment may be employed as a building block to construct larger and complex quantum networks14,15.

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The data that support the plots within this paper and other findings of this study are available from the corresponding

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References

  1. 1.

    Wehner, S., Elkouss, D. & Hanson, R. Quantum internet: a vision for the road ahead. Science 362, eaam9288 (2018).

  2. 2.

    Simon, C. Towards a global quantum network. Nat. Photon. 11, 678–680 (2017).

  3. 3.

    Gottesman, D., Jennewein, T. & Croke, S. Longer-baseline telescopes using quantum repeaters. Phys. Rev. Lett. 109, 070503 (2012).

  4. 4.

    Kómár, P. et al. A quantum network of clocks. Nat. Phys. 10, 582–587 (2014).

  5. 5.

    Pikovski, I., Zych, M., Costa, F. & Brukner, Č. Universal decoherence due to gravitational time dilation. Nat. Phys. 11, 668–672 (2015).

  6. 6.

    Chou, C.-W. et al. Functional quantum nodes for entanglement distribution over scalable quantum networks. Science 316, 1316–1320 (2007).

  7. 7.

    Moehring, D. L. et al. Entanglement of single-atom quantum bits at a distance. Nature 449, 68–71 (2007).

  8. 8.

    Yuan, Z.-S. et al. Experimental demonstration of a BDCZ quantum repeater node. Nature 454, 1098–1101 (2008).

  9. 9.

    Ritter, S. et al. An elementary quantum network of single atoms in optical cavities. Nature 484, 195–200 (2012).

  10. 10.

    Hofmann, J. et al. Heralded entanglement between widely separated atoms. Science 337, 72–75 (2012).

  11. 11.

    Usmani, I. et al. Heralded quantum entanglement between two crystals. Nat. Photon. 6, 234–237 (2012).

  12. 12.

    Bernien, H. et al. Heralded entanglement between solid-state qubits separated by three metres. Nature 497, 86–90 (2013).

  13. 13.

    Delteil, A. et al. Generation of heralded entanglement between distant hole spins. Nat. Phys. 12, 218–223 (2015).

  14. 14.

    Wallnöfer, J., Zwerger, M., Muschik, C., Sangouard, N. & Dür, W. Two-dimensional quantum repeaters. Phys. Rev. A 94, 052307 (2016).

  15. 15.

    Barrett, S. D., Rohde, P. P. & Stace, T. M. Scalable quantum computing with atomic ensembles. New J. Phys. 12, 093032 (2010).

  16. 16.

    Sangouard, N., Simon, C., de Riedmatten, H. & Gisin, N. Quantum repeaters based on atomic ensembles and linear optics. Rev. Mod. Phys. 83, 33–80 (2011).

  17. 17.

    Yang, S.-J., Wang, X.-J., Bao, X.-H. & Pan, J.-W. An efficient quantum light–matter interface with sub-second lifetime. Nat. Photon. 10, 381–384 (2016).

  18. 18.

    Bao, X.-H. et al. Efficient and long-lived quantum memory with cold atoms inside a ring cavity. Nat. Phys. 8, 517–521 (2012).

  19. 19.

    Yang, S.-J. et al. Highly retrievable spin-wave-photon entanglement source. Phys. Rev. Lett. 114, 210501 (2015).

  20. 20.

    Duan, L. M., Lukin, M. D., Cirac, J. I. & Zoller, P. Long-distance quantum communication with atomic ensembles and linear optics. Nature 414, 413–418 (2001).

  21. 21.

    Jiang, Y., Rui, J., Bao, X.-H. & Pan, J.-W. Dynamical zeroing of spin-wave momentum to suppress motional dephasing in an atomic-ensemble quantum memory. Phys. Rev. A 93, 063819 (2016).

  22. 22.

    Saffman, M., Walker, T. G. & Molmer, K. Quantum information with Rydberg atoms. Rev. Mod. Phys. 82, 2313–2363 (2010).

  23. 23.

    Li, L., Dudin, Y. O. & Kuzmich, A. Entanglement between light and an optical atomic excitation. Nature 498, 466–469 (2013).

  24. 24.

    Li, J. et al. Hong-Ou-Mandel interference between two deterministic collective excitations in an atomic ensemble. Phys. Rev. Lett. 117, 180501 (2016).

  25. 25.

    Gühne, O. & Tóth, G. Entanglement detection. Phys. Rep. 474, 1–75 (2009).

  26. 26.

    Choi, K. S., Goban, A., Papp, S. B., van Enk, S. J. & Kimble, H. J. Entanglement of spin waves among four quantum memories. Nature 468, 412–416 (2010).

  27. 27.

    Pu, Y. F. et al. Experimental entanglement of 25 individually accessible atomic quantum interfaces. Sci. Adv. 4, eaar3931 (2018).

  28. 28.

    Yan, Z. et al. Establishing and storing of deterministic quantum entanglement among three distant atomic ensembles. Nat. Commun. 8, 718 (2017).

  29. 29.

    Maring, N. et al. Photonic quantum state transfer between a cold atomic gas and a crystal. Nature 551, 485–488 (2017).

  30. 30.

    Zhao, T.-M. et al. Entangling different-color photons via time-resolved measurement and active feed forward. Phys. Rev. Lett. 112, 103602 (2014).

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Acknowledgements

This work was supported by National Key R&D Program of China (no. 2017YFA0303902), Anhui Initiative in Quantum Information Technologies, National Natural Science Foundation of China, and the Chinese Academy of Sciences.

Author information

Author notes

  1. These authors contributed equally: Bo Jing, Xu-Jie Wang.

Affiliations

  1. Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, China

    • Bo Jing
    • , Xu-Jie Wang
    • , Yong Yu
    • , Peng-Fei Sun
    • , Yan Jiang
    • , Sheng-Jun Yang
    • , Wen-Hao Jiang
    • , Xi-Yu Luo
    • , Jun Zhang
    • , Xiao Jiang
    • , Xiao-Hui Bao
    •  & Jian-Wei Pan
  2. CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, China

    • Bo Jing
    • , Xu-Jie Wang
    • , Yong Yu
    • , Peng-Fei Sun
    • , Yan Jiang
    • , Sheng-Jun Yang
    • , Wen-Hao Jiang
    • , Xi-Yu Luo
    • , Jun Zhang
    • , Xiao Jiang
    • , Xiao-Hui Bao
    •  & Jian-Wei Pan
  3. CAS-Alibaba Quantum Computing Laboratory, Shanghai, China

    • Bo Jing
    • , Xu-Jie Wang
    • , Yong Yu
    • , Peng-Fei Sun
    • , Yan Jiang
    • , Sheng-Jun Yang
    • , Wen-Hao Jiang
    • , Xi-Yu Luo
    • , Jun Zhang
    • , Xiao Jiang
    • , Xiao-Hui Bao
    •  & Jian-Wei Pan

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Contributions

X.-H.B. and J.-W.P. conceived and designed the experiment. B.J. and X.-J.W. mainly carried out the experiment and collected the data with assistance from all other authors. B.J., X.-J.W. and X.-H.B. analysed the data. B.J., X.-J.W., X.-H.B. and J.-W.P. wrote the paper with input from all other authors. X.-H.B. and J.-W.P. supervised the whole project.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to Xiao-Hui Bao or Jian-Wei Pan.

Supplementary information

  1. Supplementary Information

    Supplementary notes and figures.

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DOI

https://doi.org/10.1038/s41566-018-0342-x