Thermal critical dynamics from equilibrium quantum fluctuations

Irénée Frérot; Adam Rançon; Tommaso Roscilde

doi:10.1103/physrevlett.128.130601

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arXiv · 2110.15019

Thermal critical dynamics from equilibrium quantum fluctuations

Irénée Frérot·Adam Rançon·Tommaso Roscilde

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Abstract

We show that quantum fluctuations display a singularity at thermal critical points, involving the dynamical $z$ exponent. Quantum fluctuations, captured by the quantum variance (I. Frérot and T. Roscilde, Phys. Rev. B 94, 075121 (2016)), can be expressed via purely static quantities; this in turn allows us to extract the $z$ exponent related to the intrinsic Hamiltonian dynamics via equilibrium unbiased numerical calculations, without invoking any effective classical model for the critical dynamics. These findings illustrate that, unlike classical systems, in quantum systems static and dynamic properties remain inextricably linked even at finite-temperature transitions, provided that one focuses on static quantities that do not bear any classical analog, namely on quantum fluctuations.

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Irénée Frérot, Adam Rançon, Tommaso Roscilde. 2022-03-30. Thermal critical dynamics from equilibrium quantum fluctuations. https://doi.org/10.1103/physrevlett.128.130601

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