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Creation of memory-memory entanglement in a metropolitan quantum network
Jian-Long Liu1,2,3, Xi-Yu Luo1,2,3, Yong Yu1,2,3,4
1Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China.
Nature
|May 15, 2024
Summary
Researchers created memory-memory entanglement in a metropolitan quantum network. This milestone advances the quantum internet by demonstrating entanglement across three nodes separated by 12.5 km.
Area of Science:
- Quantum networking
- Quantum communication
Background:
- Transitioning from laboratory-based, two-node quantum network experiments to large-scale, multi-node systems is crucial for the future quantum internet.
- Previous research has focused on proof-of-principle demonstrations, highlighting the need for scalable network architectures.
Purpose of the Study:
- To establish memory-memory entanglement in a multi-node quantum network spanning a metropolitan area.
- To create a testbed for evaluating and exploring multi-node quantum network protocols.
Main Methods:
- Utilized three independent atomic ensemble quantum memory nodes with telecom conversion capabilities.
- Employed a photonic server for entanglement generation, heralded by single-photon detection.
- Implemented active phase variance stabilization for fiber links and control lasers.
- Achieved entanglement generation between any two memory nodes concurrently.
Main Results:
- Demonstrated memory-memory entanglement in a multi-node quantum network over a 12.5 km metropolitan distance.
- Confirmed that the quantum memory lifetime exceeds the round-trip communication time.
- Successfully achieved concurrent entanglement generation between multiple node pairs.
Conclusions:
- This work establishes a metropolitan-scale testbed for quantum network research.
- The findings represent a significant step towards realizing a functional quantum internet.
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