RQC Seminar

60th RQC Seminar

  • 講演者

    Prof. Salvatore Savasta
    ( Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Universit`a di Messina, Italy )

  • 日程

    2023年7月14日(金) 16:00-17:00

  • 開催場所

    ハイブリッド(ZOOM・ 研究本館3階 セミナー室(345-347) C01 )

  • 講演タイトル

    Probing the symmetry breaking of a light–matter system by an probe qubit

  • お問合せ


Hybrid quantum systems in the ultrastrong, and even more in the deep-strong coupling regimes can exhibit exotic physical phenomena [1]. In these nonperturbative regimes, a qubit–resonator system has an entangled quantum vacuum with a nonzero average photon number in the resonator, where the photons are virtual and cannot be directly detected. It has been shown theoretically that the vacuum field is able to induce the symmetry breaking of a dispersively coupled probe qubit [2]. We discuss a recent experimental observation of the parity symmetry breaking of an ancillary Xmon artificial atom induced by the field of a lumped element superconducting resonator deep-strongly coupled with a flux qubit [2]. This result opens a way to experimentally explore the novel quantum vacuum effects emerging in the deep-strong coupling regime.

[1] A. F. Kockum et al., Ultrastrong coupling between light and matter, Nat. Rev. Phys. 1, 19 (2019).

[2] L. Garziano et al., Vacuum-induced symmetry breaking in a superconducting quantum circuit, Phys. Rev. A 90,446 043817 (2014).

[3] S.-P. Wang et al., Probing the symmetry breaking of a light–matter system by an ancillary qubit (arXiv preprint arXiv:2209.05747), under review.

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