2025/06/12 by Dong Wu, Zalewski, Mika A., Wu, Denton +5 · 1 citation
Computer Science · Physics and Astronomy · #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2506.11257
openalex publication_date 2025/06/12 · openalex created_date 2025/10/11 · openalex updated_date 2026/07/29
We demonstrate entanglement between the polarization of an infrared photon and a metastable 88Sr+ ion qubit. This entanglement persists after transmitting the photon over a 2.8 km long commercial fiber deployed in an urban environment. Tomography of the ion-photon entangled state yields a fidelity of 0.949(4) within the laboratory and 0.929(5) after fiber transmission, not corrected for readout errors. Our results establish the Strontium ion as a promising candidate for metropolitan-scale quantum networking based on an atomic transition at 1092 nm, a wavelength compatible with existing telecom fiber infrastructure.