RQC Seminar

54th RQC Seminar

  • 講演者

    Dr. Fredrik Brange
    ( Department of Applied Physics, Aalto University, Finland )

  • 日程

    2023年6月23日（金） 15:00-16:00

  • 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

    Lee-Yang theory of non-equilibrium phase transitions in quantum many-body systems

  • お問合せ

    rqc_info[at]ml.riken.jp

講演概要
Phase transitions are ubiquitous phenomena in physics, characterized by the sudden change of a physical quantity in response to variations in an external control parameter. In this talk, I will introduce Lee-Yang theory as a tool for predicting and investigating phase transitions. Lee-Yang theory utilizes the zeros of a (generalized) partition function in the complex plane of the control parameter. While these zeros are non-real for finite-size systems, they may approach a point on the real axis in the thermodynamic limit, signifying the occurrence of a phase transition. I will demonstrate how the exploration of Lee-Yang zeros provides insights into equilibrium and non-equilibrium phase transitions in various quantum many-body systems, such as Bose-Einstein condensation in a gas of bosons, abrupt changes in the activity of a single-electron micromaser, and dynamical quantum phase transitions in quenched spin lattices. Moreover, I will discuss experimental approaches to determine the zeros through measurements of fluctuations in the conjugate variable of the control parameter.

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