Self-testing of a single quantum system from theory to experiment

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Type
Article
Citation
Hu, X.-M., Xie, Y., Arora, A. S., Ai, M.-Z., Bharti, K., Zhang, J., Wu, W., Chen, P.-X., Cui, J.-M., Liu, B.-H., Huang, Y.-F., Li, C.-F., Guo, G.-C., Roland, J., Cabello, A., & Kwek, L.-C. (2023). Self-testing of a single quantum system from theory to experiment. Npj Quantum Information, 9(1), Article 103. https://doi.org/10.1038/s41534-023-00769-7
Author
Hu, Xiao-Min
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Xie, Yi
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Arora, Atul Singh
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Ai, Ming-Zhong
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Bharti, Kishor
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Zhang, Jie
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Wu, Wei
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Chen, Ping-Xing
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Cui, Jin-Ming
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Liu, Bi-Heng
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Huang, Yun-Feng
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Li, Chuan-Feng
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Guo, Guang-Can
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Roland, Jeremie
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Cabello, Adan
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Kwek, Leong Chuan 
Abstract
Self-testing allows one to characterise quantum systems under minimal assumptions. However, existing schemes rely on quantum nonlocality and cannot be applied to systems that are not entangled. Here, we introduce a robust method that achieves self-testing of individual systems by taking advantage of contextuality. The scheme is based on the simplest contextuality witness for the simplest contextual quantum system—the Klyachko-Can-Binicioğlu-Shumovsky inequality for the qutrit. We establish a lower bound on the fidelity of the state and the measurements as a function of the value of the witness under a pragmatic assumption on the measurements. We apply the method in an experiment on a single trapped 40Ca+ using randomly chosen measurements and perfect detection efficiency. Using the observed statistics, we obtain an experimental demonstration of self-testing of a single quantum system.
Keywords
Date Issued
2023
Publisher
Springer
Journal
npj Quantum Information
DOI
10.1038/s41534-023-00769-7
Description
The open access publication is available at: https://doi.org/10.1038/s41534-023-00769-7