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Published on: November 11, 2013
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Heralded entanglement distribution between two absorptive quantum memories.
Xiao Liu1,2, Jun Hu1,2, Zong-Feng Li1,2
1CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China.
Nature
|June 3, 2021
Summary
Researchers demonstrated heralded entanglement distribution between absorptive quantum memories, a crucial step for building practical quantum repeaters. This advance overcomes limitations of previous methods, paving the way for high-speed quantum networks.
Area of Science:
- Quantum Information Science
- Quantum Communication
Background:
- Entanglement distribution is limited by channel loss, restricting ground-based communication to ~100 km.
- Quantum repeaters, using quantum memory and entanglement swapping, are proposed to overcome distance limitations.
- Existing quantum repeater elementary links use built-in quantum memories, facing trade-offs between multiplexing and determinism.
Purpose of the Study:
- To experimentally demonstrate heralded entanglement distribution between absorptive quantum memories.
- To overcome the limitations of built-in quantum memories in quantum repeater elementary links.
- To enable the development of efficient and practical quantum repeaters.
Main Methods:
- Constructed two quantum nodes, each with a polarization-entangled photon-pair source and a solid-state absorptive quantum memory (1 GHz bandwidth).
- Separated the nodes by 3.5 meters.
- Performed a joint Bell-state measurement in a middle station to herald entanglement distribution.
Main Results:
- Successfully achieved heralded entanglement distribution between the two remote absorptive quantum memories.
- Attained a fidelity of 80.4 ± 2.2% for the distributed entangled states.
- Demonstrated a functional elementary link for a quantum repeater.
Conclusions:
- The demonstrated system, using absorptive quantum memories, overcomes limitations of previous approaches.
- Wideband absorptive quantum memories are compatible with deterministic entanglement sources and support multiplexing.
- This work paves the way for practical solid-state quantum repeaters and high-speed quantum networks.
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