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arXiv · 2502.10715

Error-mitigated entanglement-assisted quantum process tomography

Zhihao Wu·Lingling Lao·Chengqi Zhuke·Yantong Liu·Xinfang Zhang·Shichuan Xue·Mingtang Deng·Junjie Wu·Kai Lu
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Abstract

In the era of noisy intermediate-scale quantum computing, it is of crucial importance to verify quantum processes and extract information. Quantum process tomography is a typical approach, however, both resource-intensive and vulnerable to state preparation and measurement errors. Here, we propose an error-mitigated entanglement-assisted quantum process tomography (EM-EAPT) framework to address these limitations. By leveraging a maximally entangled state to reduce state preparation complexity and integrating error mitigation techniques, our method significantly enhances robustness against SPAM errors. Experimental validation on a superconducting processor demonstrates the efficacy of EM-EAPT for two-qubit and three-qubit quantum processes. Results show more accurate average gate fidelities close to the realistic estimation, achieving 98.1$\pm$ 0.03% for a CNOT gate and 88.1%$\pm$ 0.04% for a cascaded CNOT process after error mitigation, compared to non-mitigated implementations. This work advances practical quantum verification tools for NISQ devices, enabling higher-fidelity characterization of quantum processes under realistic noise conditions.

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Zhihao Wu, Lingling Lao, Chengqi Zhuke, Yantong Liu, Xinfang Zhang, Shichuan Xue, Mingtang Deng, Junjie Wu, Kai Lu. 2025-02-15. Error-mitigated entanglement-assisted quantum process tomography. https://arxiv.org/abs/2502.10715

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