Sweeny dynamics for the random-cluster model with small $Q$

Fuente: arXiv
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Main Authors: Peng, Zirui, Elçi, Eren Metin, Deng, Youjin, Hu, Hao
Format: Preprint
Published: 2023
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author Peng, Zirui
Elçi, Eren Metin
Deng, Youjin
Hu, Hao
author_facet Peng, Zirui
Elçi, Eren Metin
Deng, Youjin
Hu, Hao
contents The Sweeny algorithm for the $Q$-state random-cluster model in two dimensions is shown to exhibit a rich mixture of critical dynamical scaling behaviors. As $Q$ decreases, the so-called critical speeding-up for non-local quantities becomes more and more pronounced. However, for some quantity of specific local pattern -- e.g., the number of half faces on the square lattice, we observe that, as $Q \to 0$, the integrated autocorrelation time $τ$ diverges as $Q^{-ζ}$, with $ζ\simeq 1/2$, leading to the non-ergodicity of the Sweeny method for $Q \to 0$. Such $Q$-dependent critical slowing-down, attributed to the peculiar form of the critical bond weight $v=\sqrt{Q}$, can be eliminated by a combination of the Sweeny and the Kawasaki algorithm. Moreover, by classifying the occupied bonds into bridge bonds and backbone bonds, and the empty bonds into internal-perimeter bonds and external-perimeter bonds, one can formulate an improved version of the Sweeny-Kawasaki method such that the autocorrelation time for any quantity is of order $O(1)$.
format Preprint
id arxiv_https___arxiv_org_abs_2308_00254
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Sweeny dynamics for the random-cluster model with small $Q$
Peng, Zirui
Elçi, Eren Metin
Deng, Youjin
Hu, Hao
Statistical Mechanics
The Sweeny algorithm for the $Q$-state random-cluster model in two dimensions is shown to exhibit a rich mixture of critical dynamical scaling behaviors. As $Q$ decreases, the so-called critical speeding-up for non-local quantities becomes more and more pronounced. However, for some quantity of specific local pattern -- e.g., the number of half faces on the square lattice, we observe that, as $Q \to 0$, the integrated autocorrelation time $τ$ diverges as $Q^{-ζ}$, with $ζ\simeq 1/2$, leading to the non-ergodicity of the Sweeny method for $Q \to 0$. Such $Q$-dependent critical slowing-down, attributed to the peculiar form of the critical bond weight $v=\sqrt{Q}$, can be eliminated by a combination of the Sweeny and the Kawasaki algorithm. Moreover, by classifying the occupied bonds into bridge bonds and backbone bonds, and the empty bonds into internal-perimeter bonds and external-perimeter bonds, one can formulate an improved version of the Sweeny-Kawasaki method such that the autocorrelation time for any quantity is of order $O(1)$.
title Sweeny dynamics for the random-cluster model with small $Q$
topic Statistical Mechanics
url https://arxiv.org/abs/2308.00254