Entanglement-enhanced quantum lock-in detection achieving Heisenberg scaling
Quantum lock-in detection (QLID) is a powerful technique for extracting weak oscillating signals within noise. While entanglement may enhance measurement precision beyond the standard quantum limit (SQL), its integration with QLID is still an experimental challenge. Here we report the first experimental realization of entanglement-enhanced QLID using two trapped <sup>40</sup>Ca<sup>+</sup> ions. We prepare a Greenberger-Horne-Zeilinger (GHZ) state using a Mϕlmer-Sϕrensen gate and then apply periodic multipulse sequences to execute QLID. Using the GHZ state, the measurement precision approaches the Heisenberg limit (Δω ∝ N<sup>-1</sup>), surpassing the SQL (Δω ∝ N<sup>-1/2</sup>) achievable with non-entangled states. Notably, QLID achieves a superior inverse-quadratic temporal scaling (Δω ∝ T<sup>-2</sup>), exceeding the conventional inverse-linear scaling (Δω ∝ T<sup>-1</sup>), regardless of entanglement. We further optimize pulse sequences for enhanced robustness against experimental errors. This work establishes a powerful pathway to Heisenberg-limited quantum sensing of weak oscillating signals within noise.
Authors
- Liang Chen (ORCID: https://orcid.org/0000-0001-9114-1885)
- Miaoqing Zhuang
- Mang Feng (ORCID: https://orcid.org/0000-0001-8652-6086)
- W.-F. Yuan (ORCID: https://orcid.org/0000-0003-2296-0443)
- Sijing Chen (ORCID: https://orcid.org/0000-0001-8849-9202)
- Fei Zhou (ORCID: https://orcid.org/0000-0002-0285-2309)
- Chaohong Lee (ORCID: https://orcid.org/0000-0001-9883-5900)
- Jiawei Zhang (ORCID: https://orcid.org/0000-0003-1638-6676)
- Jian Li (ORCID: https://orcid.org/0000-0002-4490-3530)
- G.-Y. Ding
- W.-Q. Ding
- B. Wang (ORCID: https://orcid.org/0000-0001-8242-8630)
Institutions
- Zhejiang Normal University (CN)
- Shenzhen University (CN)
- Chinese Academy of Sciences (CN)
- Wuhan Institute of Physics and Mathematics (CN)
- Shenzhen Bay Laboratory (CN)
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (CN)
- Guangzhou Building Materials Institute (CN)
- Guangdong Food Industry Research Institute (CN)
- Guangdong Institute of Intelligent Manufacturing (CN)
- University of Chinese Academy of Sciences (CN)
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (CN)
- Guangzhou Medical University (CN)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-12-06
- DOI
- https://doi.org/10.1038/s41467-025-66828-z
- Citations
- 1
- Primary Topic
- Quantum Information and Cryptography
- Type
- article
- Field-Weighted Citation Impact
- 2.48
Funders
- National Natural Science Foundation of China
- National Key Research and Development Program of China