2019/03/31 by Yong Yu, Fei Ma, Xi-Yu Luo +14 · 2 citations
Computer Science · Physics and Astronomy · #Amplitude damping channel #Cold Atom Physics and Bose-Einstein Condensates #Photon #Quantum #Quantum Information and Cryptography #Quantum channel #Quantum entanglement #Quantum information #Quantum information science #Quantum network #Quantum optics and atomic interactions #Quantum sensor #quant-ph
paper · pdf · doi:10.1038/s41586-020-1976-7
published as Nature 578, 240-245 (2020)
openalex publication_date 2020/02/12 · openalex created_date 2020/02/24 · arxiv created 2021/01/06 · arxiv updated 2021/01/07 · openalex updated_date 2026/08/05
Quantum internet will enable a number of revolutionary applications. It relies on entanglement of remote quantum memories over long distances. Despite enormous progresses so far, the maximal physical separation achieved between two nodes is 1.3 km, and challenges for long distance remain. Here we make a significant step forward by entangling two atomic ensembles in one lab via photon transmission through metropolitan-scale fibers. We use cavity enhancement to create bright atom-photon entanglement, and harness quantum frequency conversion to shift the atomic wavelength to telecom. We realize entanglement over 22 km field-deployed fibers via two-photon interference, and entanglement over 50 km coiled fibers via single-photon interference. Our experiment can be extended to physically separated nodes with similar distance as a functional segment for atomic quantum networks, thus paving the way towards establishing atomic entanglement over many nodes and over much longer distance.