Abstract

The influence of various initial magnetizations m₀ and structural defects on the nonequilibrium critical behavior of the two-dimensional Ising model is numerically simulated by Monte Carlo methods. Based on analysis of the time dependence of magnetization and the two-time dependences of autocorrelation function and dynamic susceptibility, we revealed the influence of logarithmic corrections and the crossover phenomena of percolation behavior on the nonequilibrium characteristics and the critical exponents. Violation of the fluctuation–dissipation theorem is studied, and the limiting fluctuation–dissipation ratio is calculated for the case of high-temperature initial state. The influence of various initial states on the limiting fluctuation–dissipation ratio is investigated. The nonequilibrium critical dynamics of weakly disordered systems with spin concentrations p ≥ 0.9 is shown to belong to the universality class of the nonequilibrium critical behavior of the pure model and to be characterized by the same critical exponents and the same limiting fluctuation–dissipation ratios. The nonequilibrium critical behavior of systems with p ≤ 0.85 demonstrates that the universal characteristics of the nonequilibrium critical behavior depend on the defect concentration and the dynamic scaling is violated, which is related to the influence of the crossover effects of percolation behavior.

中文翻译：

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结构缺陷对二维伊辛模型非平衡临界行为的边际效应

摘要

各种初始磁化强度m _0的影响蒙特卡罗方法对二维伊辛模型非平衡临界行为的结构缺陷进行了数值模拟。在分析磁化的时间依赖性以及自相关函数和动态磁化率的两次时间依赖性的基础上，我们揭示了对数校正和渗流行为的交叉现象对非平衡特性和临界指数的影响。研究了违反波动耗散定理的情况，并针对高温初始状态计算了极限波动耗散率。研究了各种初始状态对极限波动耗散率的影响。自旋浓度为p的弱无序系统的非平衡临界动力学≥0.9被证明属于纯模型的非平衡临界行为的普遍性类别，并且具有相同的临界指数和相同的极限波动耗散比。与系统中的非平衡的关键行为p ≤0.85表明，非平衡临界行为的普遍特性依赖于缺陷浓度和动态缩放侵犯，这是关系到的渗滤行为交叉效应的影响。