Multimode Ion-Photon Entanglement over 101 Kilometers

A three-qubit quantum network node based on trapped atomic ions is presented. The ability to establish entanglement between each individual qubit in the node and a separate photon that has traveled over a 101-km-long optical fiber is demonstrated. By sending those photons through the fiber in close succession, a remote entanglement rate is achieved that is greater than when using only a single qubit in the node. Once extended to more qubits, this multimode approach can be a useful technique to boost entanglement-distribution rates in future long-distance quantum networks of light and matter.Received 7 August 2023Revised 23 December 2023Accepted 5 March 2024DOI:https://doi.org/10.1103/PRXQuantum.5.020308Published 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 SocietyPhysics Subject Headings (PhySH)Research AreasQuantum communicationQuantum communication, protocols & technologyQuantum correlations in quantum informationQuantum entanglementQuantum networksAtomic, Molecular & OpticalQuantum Information, Science & Technology