Lee-Yang Zeros and Pseudocritical Drift in J-Q Néel-VBS Transitions

Fuente: arXiv
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Main Authors: Guo, Chunhao, Wang, Zhe, Wang, Danhe, Liu, Zenan, Zou, Haiyuan, Yan, Zheng
Format: Preprint
Published: 2026
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author Guo, Chunhao
Wang, Zhe
Wang, Danhe
Liu, Zenan
Zou, Haiyuan
Yan, Zheng
author_facet Guo, Chunhao
Wang, Zhe
Wang, Danhe
Liu, Zenan
Zou, Haiyuan
Yan, Zheng
contents Square-lattice J-Q models provide a sign-problem-free setting for probing the quantum phase transition between Néel antiferromagnet and columnar valence-bond solid. We analyze this transition through the scaling of Lee-Yang zeros, computed within stochastic series expansion quantum Monte Carlo by reweighting configurations sampled near criticality in the presence of complex source fields. Benchmark studies of the dimerized Heisenberg model and the checkerboard J-Q model validate the method, yielding stable O(3) critical scaling in the former and clear spacetime-volume scaling in the latter, as expected for a first-order transition. Applying the same analysis to the J-Q models, we find a pronounced and systematic drift of the leading-zero scaling with increasing system size, consistent with an extended pseudocritical regime. The Lee-Yang scaling implies an effective scaling dimension of the SO(5) order-parameter field that decreases with size and is consistent with vanishing in the thermodynamic limit. Such behavior lies below the scalar unitarity bound of any unitary relativistic conformal field theory in 2+1 dimensions and enforces inverse spacetime-volume scaling of the zeros, the hallmark of a first-order transition. These results support a weakly first-order interpretation of the Néel-VBS transition and establish finite-size Lee-Yang zeros as a sensitive, symmetry-resolved diagnostic of pseudocriticality and transition order in the J-Q family.
format Preprint
id arxiv_https___arxiv_org_abs_2603_15116
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Lee-Yang Zeros and Pseudocritical Drift in J-Q Néel-VBS Transitions
Guo, Chunhao
Wang, Zhe
Wang, Danhe
Liu, Zenan
Zou, Haiyuan
Yan, Zheng
Strongly Correlated Electrons
Statistical Mechanics
Square-lattice J-Q models provide a sign-problem-free setting for probing the quantum phase transition between Néel antiferromagnet and columnar valence-bond solid. We analyze this transition through the scaling of Lee-Yang zeros, computed within stochastic series expansion quantum Monte Carlo by reweighting configurations sampled near criticality in the presence of complex source fields. Benchmark studies of the dimerized Heisenberg model and the checkerboard J-Q model validate the method, yielding stable O(3) critical scaling in the former and clear spacetime-volume scaling in the latter, as expected for a first-order transition. Applying the same analysis to the J-Q models, we find a pronounced and systematic drift of the leading-zero scaling with increasing system size, consistent with an extended pseudocritical regime. The Lee-Yang scaling implies an effective scaling dimension of the SO(5) order-parameter field that decreases with size and is consistent with vanishing in the thermodynamic limit. Such behavior lies below the scalar unitarity bound of any unitary relativistic conformal field theory in 2+1 dimensions and enforces inverse spacetime-volume scaling of the zeros, the hallmark of a first-order transition. These results support a weakly first-order interpretation of the Néel-VBS transition and establish finite-size Lee-Yang zeros as a sensitive, symmetry-resolved diagnostic of pseudocriticality and transition order in the J-Q family.
title Lee-Yang Zeros and Pseudocritical Drift in J-Q Néel-VBS Transitions
topic Strongly Correlated Electrons
Statistical Mechanics
url https://arxiv.org/abs/2603.15116