RQC Seminar

277th RQC Seminar

  • Speaker

    Prof. Hisao Hayakawa
    ( Yukawa Institute for Theoretical Physics, Kyoto University )

  • Date

    16:00-17:00, (4:00 p.m.-5:00 p.m.) Wednesday, June 10, 2026

  • Venue

    Hybrid( Zoom,
    345-347 Seminar Room, 3F, Main Research Building, Wako Campus / 和光地区 研究本館3階 セミナー室 (345-347) (C01))

  • Title

    Theory of quantum and classical Mpemba effect

  • Inquiries

    norilab_rqc_assist[at]ml.riken.jp

Abstract
The Mpemba effect, a counterintuitive phenomenon in which a hotter system cools or freezes faster than a colder one, has evolved from a historical curiosity into a rigorous frontier in modern non-equilibrium statistical mechanics. While traditionally associated with the freezing of water, the effect is now understood to be a systemic relaxation anomaly occurring across a wide variety of physical systems, including granular gases, inertial suspensions, and spin glasses. Recent years have seen a surge of theoretical and experimental interest, as researchers seek to identify the universal conditions under which these anomalous relaxation pathways emerge.

In this talk, we first discuss the quantum Mpemba effect, which has become a particularly "hot" topic due to its implications for quantum thermodynamics and many-body dynamics. We review the foundational work by [1] and its extension in [2], which utilize the GKSL master equation and the eigenvalue structure of the Liouvillian to characterize the effect in quantum systems. These studies highlight how the initial state’s overlap with the slowest-decaying modes determines whether a hotter quantum system can "overtake" a cooler one during its approach to the steady state.

We then transition to recent developments in the classical Mpemba effect. We present a comprehensive analysis based on the work of [3], which explores the thermodynamic trade-offs and speed limits associated with these transitions. Furthermore, we introduce recent findings from [4], which provide a solvable model for the effect in two-dimensional systems, and discuss the latest insights from [5].

By bridging the gap between classical stochastic dynamics and quantum master equations, this presentation aims to provide a unified perspective on how non-equilibrium systems "shortcut" their way to equilibrium, with a specific focus on the unique signatures of the Mpemba effect in the quantum regime.
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References

[1] A. K. Chatterjee et al. PRL 131, 080402 (2023)

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.080402

[2] A. K. Chatterjee et al. PRA 110, 022213 (2024)

https://doi.org/10.1103/PhysRevA.110.022213

[3] T. Van Vu and H. Hayakawa, PRL 134, 107101 (2025)

https://doi.org/10.1103/PhysRevLett.134.107101

[4] H. Hayakawa and S. Takada, arXiv:2603.24148.

[5] Y. Liu et al. arXiv:2604.01543.


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