Quantum memory capable of stopping flying photons and storing their quantum coherence is essential for scalable quantum technologies. A room-temperature broadband quantum memory will enable the implementation of large-scale quantum systems for real-life applications. Due to either intrinsic high noises or short lifetime, it is still challenging to find a room-temperature broadband quantum memory beyond conceptual demonstration. Here, we present a far-off-resonance Duan-Lukin-Cirac-Zoller (FORD) protocol and demonstrate the broadband quantum memory in room-temperature atoms. We observe a low unconditional noise level of 10−4 and a cross-correlation up to 28. A strong violation of Cauchy-Schwarz inequality indicates high-fidelity generation and preservation of non-classical correlation. Furthermore, the achieved cross-correlation in room-temperature atoms exceeds the key boundary of 6 above which quantum correlation is able to violate Bell's inequality. Our results open up the door to an entirely new realm of memory-enabled quantum applications at ambient conditions.
@article{arxiv.1704.06309,
title = {A Broadband DLCZ Quantum Memory in Room-Temperature Atoms},
author = {Jian-Peng Dou and Ai-Lin Yang and Mu-Yan Du and Di Lao and Jun Gao and Lu-Feng Qiao and Hang Li and Xiao-Ling Pang and Zhen Feng and Hao Tang and Xian-Min Jin},
journal= {arXiv preprint arXiv:1704.06309},
year = {2018}
}