RQC Seminar

98th RQC Seminar

  • Speaker

    Dr. Suguru Endo
    (
    NTT Computer ＆ Data Science Laboratories, NTT Corporation )

  • Date

    16:00-17:00, November 22, 2023 (Wednesday)

  • Venue

    Hybrid(ZOOM・ Wako Main Research 3F 345-347 Seminar Room C01）

  • Title

    Generalized quantum subspace expansion for quantum error mitigation

  • Inquiries

    rqc_info[at]ml.riken.jp

Abstract
One of the major challenges for erroneous quantum computers is undoubtedly the control over the effect of noise. Considering the rapid growth of available quantum resources that are not fully fault-tolerant, it is crucial to develop practical hardware-friendly quantum error mitigation (QEM) techniques to suppress unwanted errors. Here, we propose a novel generalized quantum subspace expansion method that can handle stochastic, coherent, and algorithmic errors in quantum computers. By fully exploiting the substantially extended subspace, we can efficiently mitigate the noise present in the spectra of a given Hamiltonian without relying on any noise information. The performance of our method is discussed under two highly practical setups: the quantum subspaces are mainly spanned by powers of the noisy state and a set of error-boosted states, respectively. We also propose the resource-efficient implementation of generalized quantum subspace expansion by using the dual-state purification method and show that it can even allow for the simulation of twice the system size with moderate sampling overhead.

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