Probing Many-Body Bell Correlation Depth with Superconducting Qubits

Quantum nonlocality describes a stronger form of quantum correlation than that of entanglement. It refutes Einstein’s belief of local realism and is among the most distinctive and enigmatic features of quantum mechanics. It is a crucial resource for achieving quantum advantages in a variety of practical applications, ranging from cryptography and certified random number generation via self-testing to machine learning. Nevertheless, the detection of nonlocality, especially in quantum many-body systems, is notoriously challenging. Here, we report an experimental certification of genuine multipartite Bell-operator correlations, which signal nonlocality in quantum many-body systems, up to 24 qubits with a fully programmable superconducting quantum processor. In particular, we employ energy as a Bell-operator correlation witness and variationally decrease the energy of a many-body system across a hierarchy of thresholds, below which an increasing Bell-operator correlation depth can be certified from experimental data. We variationally prepare the low-energy state of a two-dimensional honeycomb model with 73 qubits and certify its Bell-operator correlations by measuring an energy that surpasses the corresponding classical bound with up to 48 standard deviations. In addition, we variationally prepare a sequence of low-energy states and certify their genuine multipartite Bell-operator correlations up to 24 qubits via energies measured efficiently by parity oscillation and multiple quantum coherence techniques. Our results establish a viable approach for preparing and certifying multipartite Bell-operator correlations, which provide not only a finer benchmark beyond entanglement for quantum devices, but also a valuable guide toward exploiting multipartite Bell correlations in a wide spectrum of practical applications.

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Publication Details

Journal
Physical Review X
Published
2025-04-22
DOI
https://doi.org/10.1103/physrevx.15.021024
Citations
3
Primary Topic
Quantum Mechanics and Applications
Type
article
Field-Weighted Citation Impact
3.74

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article

Probing Many-Body Bell Correlation Depth with Superconducting Qubits

Ziqi Tan, Yiren Zou, Aosai Zhang, Zhen Wang et al.
3 citations
Physical Review X
Quantum Mechanics and Applications
3.74
article

Probing Many-Body Bell Correlation Depth with Superconducting Qubits

Ziqi Tan, Yiren Zou, Aosai Zhang, Zhen Wang, Jinfeng Deng, Zheng-Zhi Sun, Tingting Li, Chao Song, Fanhao Shen, Hekang Li, Chuanyu Zhang, Yaozu Wu, Dong-Ling Deng, Qiujiang Guo, Zehang Bao, Pengfei Zhang, Feitong Jin, H. Wang, Xuhao Zhu, Jiarun Zhong, Zitian Zhu, Wenjie Jiang, Jordi Tura, Mengyao Hu, Ke Wang, Zhide Lu, Zhengyi Cui, Shibo Xu, Patrick Emonts, Ning Wang, Xu Zhang, Hang Dong, Weikang Li, Zixuan Song, Jiachen Chen, Yu Gao
article en
3 citations

Abstract

Quantum nonlocality describes a stronger form of quantum correlation than that of entanglement. It refutes Einstein’s belief of local realism and is among the most distinctive and enigmatic features of quantum mechanics. It is a crucial resource for achieving quantum advantages in a variety of practical applications, ranging from cryptography and certified random number generation via self-testing to machine learning. Nevertheless, the detection of nonlocality, especially in quantum many-body systems, is notoriously challenging. Here, we report an experimental certification of genuine multipartite Bell-operator correlations, which signal nonlocality in quantum many-body systems, up to 24 qubits with a fully programmable superconducting quantum processor. In particular, we employ energy as a Bell-operator correlation witness and variationally decrease the energy of a many-body system across a hierarchy of thresholds, below which an increasing Bell-operator correlation depth can be certified from experimental data. We variationally prepare the low-energy state of a two-dimensional honeycomb model with 73 qubits and certify its Bell-operator correlations by measuring an energy that surpasses the corresponding classical bound with up to 48 standard deviations. In addition, we variationally prepare a sequence of low-energy states and certify their genuine multipartite Bell-operator correlations up to 24 qubits via energies measured efficiently by parity oscillation and multiple quantum coherence techniques. Our results establish a viable approach for preparing and certifying multipartite Bell-operator correlations, which provide not only a finer benchmark beyond entanglement for quantum devices, but also a valuable guide toward exploiting multipartite Bell correlations in a wide spectrum of practical applications.

Physical Review XVol. 15(2)
Leiden University (NL), Hefei University (CN), Computer Algorithms for Medicine (AT), ShangHai JiAi Genetics & IVF Institute (CN), Zhejiang University (CN), Tsinghua University (CN)
Northwest Airlines, European Commission, National Natural Science Foundation of China, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Tsinghua University, Zhejiang University, Horizon 2020 Framework Programme, HORIZON EUROPE Framework Programme, National Key Research and Development Program of China, Natural Science Foundation of Zhejiang Province
Openalex Percentile: Top 8%
Quantum Mechanics and Applications
3.74
DOIOpen Access PDFOpenAlex
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