Article
Methods
Time sequences
Our experiment runs periodically, with each period being composed of
an atomic loading phase and an entangling phase. Each loading phase
takes 18 ms, during which we reload and cool the atoms and perform
active phase-locking. In the entangling phase lasting 2 ms, we repeat
entangling trials. For the SPI experiment, each trial lasts 5 μs including
3 μs for optical pumping and 2 μs for the write and read process. For the
TPI experiment, each trial lasts 11 μs including 3 μs for optical pumping
and 8 μs for the write and read process. The storage duration (relative
delay of the read pulse in comparison with the write pulse) is 7 μs for
the TPI experiment and 100 ns for the SPI experiment.
Data availability
The data that support the plots within this paper and other findings of
this study are available from the corresponding author upon reason-
able request.
Acknowledgements This work was supported by the National Key R&D Program of China
(2017YFA0303902, 2018YFB0504300, 2017YFA0304000), the Anhui Initiative in Quantum
Information Technologies, the National Natural Science Foundation of China and the Chinese
Academy of Sciences. We thank QuantumCTek for providing the field-deployed fibres.Author contributions X.-H.B. and J.-W.P. conceived the research. Q.Z., X.-H.B. and J.-W.P.
designed the experiment. Y.Y., X.-Y.L., B.J., P.-F.S., R.-Z.F., C.-W.Y. and X.-H.B. carried out the
experiment with assistance from all other authors. F.M., M.-Y.Z., X.-P.X. and Q.Z. built the QFC
module. W.-J.Z., L.-X.Y. and Z.W. fabricated the superconducting nanowire single-photon
detectors. Y.Y., Q.Z., X.-H.B. and J.-W.P. analysed the data and wrote the paper with input from
all other authors.
Competing interests The authors declare no competing interests.Additional information
Supplementary information is available for this paper at https://doi.org/10.1038/s41586-020-
1976-7.
Correspondence and requests for materials should be addressed to Q.Z., X.-H.B. and J.-W.P.
Reprints and permissions information is available at http://www.nature.com/reprints.