一维长程自回避行走:蒙特卡洛研究
Long-range self-avoiding walk in one dimension: a Monte Carlo study
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- Guizhou University(贵州大学)
- University of Science and Technology of China(中国科学技术大学)
- Hefei National Laboratory(合肥国家实验室)
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中文总结 AI 辅助
本研究通过大规模蒙特卡洛模拟,精确估计了一维长程自回避行走的临界参数,确定了长程与短程普适类的分界,并验证了长程 O(n) 模型的普适性图景。
中文摘要 AI 辅助
我们在巨正则系综中研究一维长程自回避行走,其中长度为 $r$ 的跳跃的统计权重按 $r^{-(d+\sigma)}$ 的代数形式衰减。利用具有高效不可逆更新方案的大规模蒙特卡洛模拟,我们获得了临界逸度 $z_c$、普适 Binder 比 $Q_N^c$、关联长度指数 $\nu$ 和反常维度 $\eta$ 的高精度估计。对于 $\sigma>1$,临界逸度随 $\sigma$ 平滑变化,而 Binder 比和临界指数与短程普适类保持一致。相比之下,对于 $\sigma \le 1$,结果明显偏离短程行为,确定 $\sigma=1$ 为长程和短程区域之间的边界。在 $1/2 < \sigma \leq 1$ 的长程 Wilson-Fisher 区域中,$\eta$ 与长程高斯不动点预测 $\eta_{\mathrm{GFP}}=2-\sigma$ 一致,而 $Q_N^c$ 和 $\nu$ 随 $\sigma$ 非平凡变化,并在 $\sigma=1$ 处表现出不连续跳跃。这些发现与最近提出的长程 O$(n)$ 模型在 $(d,\sigma)$ 平面上的普适性图景高度一致,其中自回避行走对应于 $n\to0$ 极限。
英文摘要
We study the one-dimensional long-range self-avoiding walk in the grand-canonical ensemble where the statistical weight of a jump of length $r$ decays algebraically as $r^{-(d+σ)}$. Using large-scale Monte Carlo simulations with an efficient irreversible update scheme, we obtain high-precision estimates of the critical fugacity $z_c$, the universal Binder ratio $Q_N^c$, the correlation-length exponent $ν$, and the anomalous dimension $η$. For $σ>1$, the critical fugacity varies smoothly with $σ$, while the Binder ratio and the critical exponents remain consistent with the short-range universality class. For $σ\le 1$, by contrast, the results clearly depart from short-range behavior, identifying $σ=1$ as the boundary between long-range and short-range regimes. In the long-range Wilson-Fisher regime with $1/2 < σ\leq 1$, $η$ agrees with the long-range Gaussian-fixed-point prediction $η_{\mathrm{GFP}}=2-σ$, whereas $Q_N^c$ and $ν$ vary nontrivially with $σ$ and exhibit discontinuous jumps at $σ=1$. These findings are in good agreement with the recently proposed universality diagram in the $(d,σ)$ plane for long-range O$(n)$ models, with the self-avoiding walk corresponding to the $n\to0$ limit.