In this paper we report an experiment that verifies an atomic-ensemble quantum memory via a measurement-device-independent scheme. A single photon generated via Rydberg blockade in one atomic ensemble is stored in another atomic ensemble via electromagnetically induced transparency. After storage for a long duration, this photon is retrieved and interfered with a second photon to perform joint Bell-state measurement (BSM). Quantum state for each photon is chosen based on a quantum random number generator respectively in each run. By evaluating correlations between the random states and BSM results, we certify that our memory is genuinely entanglement-preserving.
@article{arxiv.2104.14723,
title = {Measurement-Device-Independent Verification of a Quantum Memory},
author = {Yong Yu and Peng-Fei Sun and Yu-Zhe Zhang and Bing Bai and Yu-Qiang Fang and Xi-Yu Luo and Zi-Ye An and Jun Li and Jun Zhang and Feihu Xu and Xiao-Hui Bao and Jian-Wei Pan},
journal= {arXiv preprint arXiv:2104.14723},
year = {2021}
}