RQC Seminar

42nd RQC Seminar

  • 講演者

    Prof. Kyungwon An
    (Seoul National University）

  • 日程

    2023年4月20日（木）16:00-17:00（JST）

  • 開催場所

    ハイブリッド（Zoom ・ 理研　和光事業所　本部棟2階 大会議室）

  • 講演タイトル

    A photonic quantum engine driven by superradiance

  • お問合せ

    rqc_info[at]ml.riken.jp

講演概要
A superradiant state is a special quantum state of atoms capable of producing superradiance immediately without a time delay. We can prepare a superradiant state in an optical cavity by exciting N atoms in the same superposition state of the ground and excited states. These phase-correlated atoms generate superradiance in the cavity even when the mean number of intracavity atoms is much less than unity [J. Kim et al., Science 359, 662 (2018)]. The superradiant state has been used to realize the long-sought superabsorption, the opposite of superradiance, by reversing the superradiance process in time [D. Yang et al., Nature Photonics 15, 272 (2021)]. Recently, we have realized a photonic quantum engine, where the atoms entering the cavity are our fuel and the photons are an engine medium exerting radiation pressure on the mirrors. Our engine operates between a thermal state and a superradiant state of the reservoir at the same reservoir temperature. The effective engine temperature in the volume-expansion phase rose up to 150,000K because of the large ergotropy transfer from the reservoir through superradiance. The corresponding engine efficiency was as high as 98% [J.-U. Kim et al., Nature Photonics 16, 707 (2022)].


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