Quantum gate identification: Error analysis, numerical results and optical experiment

Yuanlong Wang, Qi Yin, Daoyi Dong*, Bo Qi, Ian R. Petersen, Zhibo Hou, Hidehiro Yonezawa, Guo Yong Xiang

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    31 Citations (Scopus)

    Abstract

    The identification of an unknown quantum gate is a significant issue in quantum technology. In this paper, we propose a quantum gate identification method within the framework of quantum process tomography. In this method, a series of pure states are applied to the gate and then a fast state tomography on the output states is performed and the data are used to reconstruct the quantum gate. The algorithm has computational complexity O(d3) with the system dimension d. The identification approach is compared with the maximum likelihood estimation method for the running time, which shows an efficiency advantage of our method. An error upper bound is established for the identification algorithm and the robustness of the algorithm against impurities in the input states is also tested. We perform a quantum optical experiment on a single-qubit Hadamard gate to verify the effectiveness of the identification algorithm.

    Original languageEnglish
    Pages (from-to)269-279
    Number of pages11
    JournalAutomatica
    Volume101
    DOIs
    Publication statusPublished - Mar 2019

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