Bell nonlocality with directly generated telecom-band spin-photon entanglement
Abstract
Quantum nonlocality, typically revealed through entanglement distribution across quantum networks, is a cornerstone of quantum information science. Long-distance distribution of entanglement requires the information carrier, i.e. flying photons, to operate in the minimum-loss telecom band of optical fiber. While extensive efforts have been devoted to the direct generation of entanglement between C-band telecom photons and various stationary spins, the verification of quantum nonlocality remains an outstanding challenge. Here, utilizing a dipole transition in rubidium atoms with a wavelength of 1530 nm and a cavity-assisted protocol, we achieve resonant excitation and direct emission of C-band telecom photons from a single atom, generating spin-photon entanglement with a measured Bell state fidelity exceeding 91.4%. We then verify Bell nonlocality by observing a Bell inequality violation of 2.455(77) > 2 using this high-quality entangled pair. These results extend the wavelength of a single-atom quantum emitter to the telecom C-band, achieving sufficiently high-fidelity spin-photon entanglement to finally verify Bell nonlocality. This work thereby provides a promising building block for a large-scale atom-based quantum network capable of distributed quantum metrology and long-distance quantum communication.
Versions
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BibTeX
@misc{huang2026bell,
title = {{Bell nonlocality with directly generated telecom-band spin-photon entanglement}},
author = {Dong-Yu Huang and Jian Wang and Xiao-Long Zhou and Ze-Min Shen and Si-Jian He and Qi-Yang Huang and Yi-Jia Liu and Yu-Shu Chen and Quan Jiang and Chuan-Feng Li and Guang-Can Guo},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.08109},
eprint = {2608.08109},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.08109},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Bell nonlocality with directly generated telecom-band spin-photon entanglement
AU - Dong-Yu Huang
AU - Jian Wang
AU - Xiao-Long Zhou
AU - Ze-Min Shen
AU - Si-Jian He
AU - Qi-Yang Huang
AU - Yi-Jia Liu
AU - Yu-Shu Chen
AU - Quan Jiang
AU - Chuan-Feng Li
AU - Guang-Can Guo
PY - 2026
DA - 2026/08/08
PB - arXiv
DO - 10.48550/arxiv.2608.08109
UR - https://arxiv.org/abs/2608.08109
AB - Quantum nonlocality, typically revealed through entanglement distribution across quantum networks, is a cornerstone of quantum information science. Long-distance distribution of entanglement requires the information carrier, i.e. flying photons, to operate in the minimum-loss telecom band of optical fiber. While extensive efforts have been devoted to the direct generation of entanglement between C-band telecom photons and various stationary spins, the verification of quantum nonlocality remains an outstanding challenge. Here, utilizing a dipole transition in rubidium atoms with a wavelength of 1530 nm and a cavity-assisted protocol, we achieve resonant excitation and direct emission of C-band telecom photons from a single atom, generating spin-photon entanglement with a measured Bell state fidelity exceeding 91.4%. We then verify Bell nonlocality by observing a Bell inequality violation of 2.455(77) > 2 using this high-quality entangled pair. These results extend the wavelength of a single-atom quantum emitter to the telecom C-band, achieving sufficiently high-fidelity spin-photon entanglement to finally verify Bell nonlocality. This work thereby provides a promising building block for a large-scale atom-based quantum network capable of distributed quantum metrology and long-distance quantum communication.
ER -