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arXiv · 2409.06547

Imaginary-time Mpemba effect in quantum many-body systems

Wei-Xuan Chang·Shuai Yin·Shi-Xin Zhang·Zi-Xiang Li
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Abstract

Various exotic phenomena emerge in non-equilibrium quantum many-body systems. The Mpemba effect, denoting the situation where a hot system freezes faster than the colder one, is a counterintuitive non-equilibrium phenomenon that has attracted enduring interest for more than half a century. In this Letter, we report a novel phenomenon of the Mpemba effect in the imaginary-time relaxation dynamics in quantum many-body systems, dubbed as imaginary-time Mpemba effect (ITME). Through numerically exact quantum Monte-Carlo (QMC) simulation, we unambiguously demonstrate that in different classes of interacting quantum models, the initial states with higher energy are relaxed faster than lower-energy initial states in the process of imaginary-time relaxation. The emergence of ITME is intimately associated with the low-energy excitations in quantum many-body systems. More crucially, since imaginary-time dynamics is broadly applied in numerical simulation on the quantum many-body ground states, the discovery of ITME potentially provides a new pathway to expedite the quantum many-body computation, particularly for QMC involving the sign problem.

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Wei-Xuan Chang, Shuai Yin, Shi-Xin Zhang, Zi-Xiang Li. 2024-09-10. Imaginary-time Mpemba effect in quantum many-body systems. https://doi.org/10.1103/dvrt-n2hq

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