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arXiv · 2006.05631

Long-lived and multiplexed atom-photon entanglement interface with feed-forward-controlled readouts

Shengzhi Wang·Minjie Wang·Yafei Wen·Zhongxiao Xu·Tengfei Ma·Shujing Li·Hai Wang
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Abstract

The quantum interface (QI) that generates entanglement between photonic and spin-wave (atomic memory) qubits is a basic building block for quantum repeaters. Realizing ensemble-based repeaters in practice requires quantum memory providing long lifetime and multimode capacity. Significant progresses have been achieved on these separate goals. The remaining challenge is to combine long-lived and multimode memories into a single QI. Here, by establishing multimode, magnetic-field-insensitive and long-wavelength spin-wave storage in laser-cooled atoms that are placed inside a phase-passively-stabilized polarization interferometer, we constructed a multiplexed QI that stores up to three long-lived spin-wave qubits. Using a feed-forward-controlled system, we demonstrated that the multiplexed QI gives rise to a 3-fold increase in the atom-photon (photon-photon) entanglement-generation probability compared to single-mode QIs. The measured Bell parameter is 2.5+/-0.1 combined with a memory lifetime up to 1ms. The presented work represents a key step forward in realizing fiber-based long-distance quantum communications.

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Shengzhi Wang, Minjie Wang, Yafei Wen, Zhongxiao Xu, Tengfei Ma, Shujing Li, Hai Wang. 2020-06-10. Long-lived and multiplexed atom-photon entanglement interface with feed-forward-controlled readouts. https://arxiv.org/abs/2006.05631

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