Abstract
For scalable quantum communication and networks, a key step is to realize a quantum repeater node that can efficiently connect different segments of atom-photon entanglement using quantum memories. We report a compact and hardware-efficient realization of a quantum repeater node using a single atomic ensemble for multicell quantum memories. A millisecond lifetime is achieved for individual memory cells after suppressing the magnetic-field-induced inhomogeneous broadening and the atomic-motion-induced spin-wave dephasing. Based on these long-lived memory cells, we achieve heralded asynchronous entanglement generation in two quantum repeater segments one after another and then an on-demand entanglement connection of these two repeater segments. As another application of the multicell atomic quantum memory, we further demonstrate storage and on-demand retrieval of heralded atomic spin-wave qubits by implementing a random access quantum memory with individual addressing capacity. This work provides a promising constituent for efficient realization of quantum repeaters for large-scale quantum networks.
- Received 29 April 2021
- Revised 9 August 2021
- Accepted 13 September 2021
DOI:https://doi.org/10.1103/PRXQuantum.2.040307
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Photons are ideal carriers of information for long-distance quantum communication and large-scale quantum networks; however, they are still subject to exponential loss in optical fibers. To overcome this problem, quantum repeaters are required that divide the communication into multiple segments and use quantum memories at the nodes to connect segments of entanglement. A key step for scalable quantum networks is thus to realize quantum repeater nodes that can efficiently connect different segments of atom-photon entanglement using quantum memories with long enough coherence to boost the connection success probability.
Here, we report a compact and hardware-efficient realization of a quantum repeater node using a single atomic ensemble for multicell quantum memories. A millisecond lifetime is achieved for individual memory cells after suppressing the magnetic-field-induced inhomogeneous broadening and the atomic-motion-induced spin-wave dephasing. Based on these long-lived memory cells, we achieve heralded asynchronous entanglement generation in two quantum repeater segments one after another and then an on-demand entanglement connection of these two repeater segments. As another application of the multicell atomic quantum memory, we also demonstrate storage and on-demand retrieval of heralded atomic spin-wave qubits by implementing a random access quantum memory with individual addressing of multiple long-lived memory cells.
Compared with the previous work, this experimental implementation of the quantum repeater node has the advantages of being compact and hardware efficient, less vulnerable to environmental noise, and more convenient for manipulation of information stored in different memory cells. The experiment thus provides a promising constituent for efficient realization of quantum repeaters for future large-scale quantum networks.