Singularity and universality from von Neumann to Rényi entanglement entropy and disorder operator in Motzkin chains

Fuente: arXiv
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Main Authors: Wang, Jianyu, Liu, Zenan, Yan, Zheng, Wu, Congjun
Format: Preprint
Published: 2025
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_version_ 1866917927107690496
author Wang, Jianyu
Liu, Zenan
Yan, Zheng
Wu, Congjun
author_facet Wang, Jianyu
Liu, Zenan
Yan, Zheng
Wu, Congjun
contents The Rényi entanglement entropy is widely used in studying quantum entanglement properties in strongly correlated systems, whose analytic continuation as the Rényi index $n \to 1$ is often believed to yield the von Neumann entanglement entropy. However, earlier findings indicate that this process exhibits a singularity for the colored Motzkin spin chain problem, leading to different scaling behaviors of $\sim \sqrt{l}$ and $\sim \log{l}$ for the von Neumann and Rényi entropies, respectively. Our analytical and numerical calculations confirm this transition, which can be explained by the exponentially increasing density of states in the entanglement spectrum that we extract numerically. Disorder operators are further employed under various symmetries to study such a system. Both analytical and numerical results demonstrate that the scaling of the disorder operators also follows $\log{l}$ as the leading behavior, matching that of the Rényi entropy. We propose that the coefficient of the term $\log{l}$ is a universal constant shared by both the Rényi entropies and disorder operators. This universal constant could potentially help capture the underlying constraint physics of Motzkin walks.
format Preprint
id arxiv_https___arxiv_org_abs_2501_17368
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Singularity and universality from von Neumann to Rényi entanglement entropy and disorder operator in Motzkin chains
Wang, Jianyu
Liu, Zenan
Yan, Zheng
Wu, Congjun
Strongly Correlated Electrons
Statistical Mechanics
Quantum Physics
The Rényi entanglement entropy is widely used in studying quantum entanglement properties in strongly correlated systems, whose analytic continuation as the Rényi index $n \to 1$ is often believed to yield the von Neumann entanglement entropy. However, earlier findings indicate that this process exhibits a singularity for the colored Motzkin spin chain problem, leading to different scaling behaviors of $\sim \sqrt{l}$ and $\sim \log{l}$ for the von Neumann and Rényi entropies, respectively. Our analytical and numerical calculations confirm this transition, which can be explained by the exponentially increasing density of states in the entanglement spectrum that we extract numerically. Disorder operators are further employed under various symmetries to study such a system. Both analytical and numerical results demonstrate that the scaling of the disorder operators also follows $\log{l}$ as the leading behavior, matching that of the Rényi entropy. We propose that the coefficient of the term $\log{l}$ is a universal constant shared by both the Rényi entropies and disorder operators. This universal constant could potentially help capture the underlying constraint physics of Motzkin walks.
title Singularity and universality from von Neumann to Rényi entanglement entropy and disorder operator in Motzkin chains
topic Strongly Correlated Electrons
Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2501.17368