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Experimental demonstration of memory-enhanced scaling for entanglement connection of quantum repeater segments

Nature Photonics volume 15, pages 374–378 (2021)Cite this article

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Abstract

The quantum repeater protocol is a promising approach for implementing long-distance quantum communication and large-scale quantum networks. A key idea of the quantum repeater protocol is to use long-lived quantum memories to achieve an efficient entanglement connection between different repeater segments, with polynomial scaling. Here, we report an experiment that realizes the efficient connection of two quantum repeater segments via on-demand entanglement swapping through the use of two atomic quantum memories with storage times of tens of milliseconds. With the memory enhancement, acceleration in the scaling is demonstrated in the rate for a successful entanglement connection. Experimental realization of the entanglement connection of two quantum repeater segments with an efficient memory-enhanced scaling demonstrates a key advantage of the quantum repeater protocol, creating a cornerstone for the development of future large-scale quantum networks.

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Fig. 1: The quantum repeater protocol and the experimental set-up.
Fig. 2: The quantum repeater node with long memory time.
Fig. 3: Entanglement connection of two quantum repeater segments.
Fig. 4: Memory-enhanced scaling of efficiencies for entanglement connection.

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.

Code availability

The code used for quantum state tomography is available from the corresponding author upon reasonable request.

References

  1. Kimble, H. J. The quantum internet. Nature 453, 1023–1030 (2008).

    Article  ADS  Google Scholar 

  2. Briegel, H.-J., Dür, W., Cirac, J. I. & Zoller, P. Quantum repeaters: the role of imperfect local operations in quantum communication. Phys. Rev. Lett. 81, 5932–5935 (1998).

    Article  ADS  Google Scholar 

  3. 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).

    Article  ADS  Google Scholar 

  4. 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).

    Article  ADS  Google Scholar 

  5. Bennett, C. H. et al. Teleporting an unknown quantum state via dual classical and Einstein–Podolsky–Rosen channels. Phys. Rev. Lett. 70, 1895–1899 (1993).

    Article  ADS  MathSciNet  Google Scholar 

  6. Bennett, C. H. et al. Purification of noisy entanglement and faithful teleportation via noisy channels. Phys. Rev. Lett. 76, 722–725 (1996).

    Article  ADS  Google Scholar 

  7. Hammerer, K., Sorensen, A. S. & Polzik, E. S. Quantum interface between light and atomic ensembles. Rev. Mod. Phys. 82, 1041–1093 (2010).

    Article  ADS  Google Scholar 

  8. Chou, C.-W. et al. Measurement-induced entanglement for excitation stored in remote atomic ensembles. Nature 438, 828–832 (2005).

    Article  ADS  Google Scholar 

  9. Chaneliere, T. et al. Storage and retrieval of single photons transmitted between remote quantum memories. Nature 438, 833–836 (2005).

    Article  ADS  Google Scholar 

  10. Eisaman, M. D. et al. Electromagnetically induced transparency with tunable single-photon pulses. Nature 438, 837–841 (2005).

    Article  ADS  Google Scholar 

  11. Simon, J., Tanji, H., Ghosh, S. & Vuletic, V. Single-photon bus connecting spin–wave quantum memories. Nat. Phys. 3, 765–769 (2007).

    Article  Google Scholar 

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

    Article  ADS  Google Scholar 

  13. de Riedmatten, H., Afzelius, M., Staudt, M. U., Simon, C. & Gisin, N. A solid-state light–matter interface at the single-photon level. Nature 456, 773–777 (2008).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  15. Yu, Y. et al. Entanglement of two quantum memories via fibres over dozens of kilometres. Nature 578, 240–245 (2020).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  18. Stephenson, L. J. et al. High-rate, high-fidelity entanglement of qubits across an elementary quantum network. Phys. Rev. Lett. 124, 110501 (2020).

    Article  ADS  Google Scholar 

  19. Slodička, L. et al. Atom–atom entanglement by single-photon detection. Phys. Rev. Lett. 110, 083603 (2013).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  21. Kaneda, F., Xu, F., Chapman, J. & Kwiat, P. G. Quantum-memory-assisted multi-photon generation for efficient quantum information processing. Optica 4, 1034–1037 (2017).

    Article  ADS  Google Scholar 

  22. Bhaskar, M. K. et al. Experimental demonstration of memory-enhanced quantum communication. Nature 580, 60–64 (2020).

    Article  ADS  Google Scholar 

  23. Azuma, K., Tamaki, K. & Lo, H.-K. All-photonic quantum repeaters. Nat. Commun. 6, 6787 (2015).

    Article  ADS  Google Scholar 

  24. Li, Z.-D. et al. Experimental quantum repeater without quantum memory. Nat. Photon. 13, 644–648 (2019).

    Article  ADS  Google Scholar 

  25. Hasegawa, Y. et al. Experimental time-reversed adaptive Bell measurement towards all-photonic quantum repeaters. Nat. Commun. 10, 378 (2019).

    Article  ADS  Google Scholar 

  26. Zhao, Z. et al. Experimental realization of entanglement concentration and a quantum repeater. Phys. Rev. Lett. 90, 207901 (2003).

    Article  ADS  Google Scholar 

  27. Ekert, A. K. Quantum cryptography based on Bell’s theorem. Phys. Rev. Lett. 67, 661–663 (1991).

    Article  ADS  MathSciNet  Google Scholar 

  28. Zhao, R. et al. Long-lived quantum memory. Nat. Phys. 5, 100–104 (2009).

    Article  Google Scholar 

  29. 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).

    Article  ADS  Google Scholar 

  30. Dudin, Y. O., Zhao, R., Kennedy, T. A. B. & Kuzmich, A. Light storage in a magnetically dressed optical lattice. Phys. Rev. A 81, 041805 (2010).

    Article  ADS  Google Scholar 

  31. Fleischhauer, M. & Lukin, M. D. Dark-state polaritons in electromagnetically induced transparency. Phys. Rev. Lett. 84, 5094–5097 (2000).

    Article  ADS  Google Scholar 

  32. Stute, A. et al. Tunable ion–photon entanglement in an optical cavity. Nature 485, 482–485 (2012).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  34. Krutyanskiy, V. et al. Light–matter entanglement over 50 km of optical fibre. npj Quantum Inf. 5, 72 (2019).

    Article  ADS  Google Scholar 

  35. Chang, W. et al. Long-distance entanglement between a multiplexed quantum memory and a telecom photon. Phys. Rev. X 9, 041033 (2019).

    Google Scholar 

Download references

Acknowledgements

This work was supported by the National Key Research and Development Program of China (2016YFA0301902), the Beijing Academy of Quantum Information Sciences, the Frontier Science Center for Quantum Information of the Ministry of Education of China and the Tsinghua University Initiative Scientific Research Program. Y.K.W. acknowledges support from the Shuimu Tsinghua Scholar Program and the International Postdoctoral Exchange Fellowship Program.

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Author notes

  1. Yun-Fei Pu

    Present address: Institute for Experimental Physics, University of Innsbruck, Innsbruck, Austria

  2. Nan Jiang

    Present address: Department of Physics, Beijing Normal University, Beijing, China

  3. These authors contributed equally. Yun-Fei Pu, Sheng Zhang.

Authors and Affiliations

  1. Center for Quantum Information, IIIS, Tsinghua University, Beijing, China

    Yun-Fei Pu, Sheng Zhang, Yu-Kai Wu, Nan Jiang, Wei Chang, Chang Li & Lu-Ming Duan

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Contributions

L.-M.D. designed the experiment and supervised the project. Y.-F.P., S.Z., N.J., W.C. and C.L. performed the experiment. Y.-F.P. and S.Z. analysed the data. Y.-K.W. contributed materials and analysis tools. Y.-F.P., S.Z., Y.-K.W. and L.-M.D. wrote the manuscript.

Corresponding author

Correspondence to Lu-Ming Duan.

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The authors declare no competing interests.

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Peer review information Nature Photonics thanks Bing Qi and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Six sections and Figs. 1–6.

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Pu, YF., Zhang, S., Wu, YK. et al. Experimental demonstration of memory-enhanced scaling for entanglement connection of quantum repeater segments. Nat. Photonics 15, 374–378 (2021). https://doi.org/10.1038/s41566-021-00764-4

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