标题： 结构-动力学关联及其与易碎性和动力学异质性的联系 显示英文标题

标题： Structure-Dynamics Correlation and Its Link to Fragility and Dynamic Heterogeneity

摘要： 理解结构、动力学与易脆性（即弛豫时间随温度降低而增长的速率）之间的关系是揭示玻璃化转变的核心。易脆性通常与动力学异质性相关联，因此普遍假设如果结构影响动力学，那么更易碎的系统应该表现出更强的结构-动力学关联。 在这项研究中，我们使用三种模型系统来测试这一假设的普适性：Lennard-Jones (LJ) 和 Weeks-Chandler-Andersen 系统，通过密度调节易脆性；以及一个修改后的 LJ (q, p) 系统，通过改变势能软度来调节易脆性。我们采用源自平均场囚禁势的结构序参量，并在宏观和微观层面分析能量壁垒。 虽然适当定义的宏观能量壁垒斜率与易脆性相关，但未发现微观能量壁垒的一致相关性。相反，后者显示出与从等构型系综计算得到的独立结构动力学测量指标的强烈相关性。 令人惊讶的是，在两个具有最强结构-动力学关联的系统中，LJ 在 ρ = 1.1 的系统和 (8, 5) 模型分别是各自类别中最不易碎和最易碎的系统。这些系统表现出广泛的移动性分布、双峰位移剖面和高非高斯参数，这些都是动力学异质性的标志。 然而，它们的动力学易感性仍然较低，表明空间关联和时间异质性之间存在解耦现象。这两个系统都处于焓主导的区域且接近自旋临界点，这表明机械不稳定性是异质性的一个来源。 这些发现挑战了关于易脆性、异质性和结构-动力学关联的传统联系。 显示英文摘要

摘要： Understanding the connection between structure, dynamics, and fragility (the rate at which relaxation time grow with decreasing temperature) is central to unraveling the glass transition. Fragility is often linked to dynamic heterogeneity, and thus it is commonly assumed that if structure influences dynamics, more fragile systems should exhibit stronger structure dynamics correlations. In this study, we test the generality of this assumption using three model systems: Lennard-Jones (LJ) and Weeks--Chandler--Andersen, where fragility is tuned via density, and a modified LJ (q, p) system, where potential softness is changed to vary fragility. We employ a structural order parameter derived from the mean field caging potential and analyze energy barriers at both macroscopic and microscopic levels. While the macroscopic slope of the energy barrier, suitably defined, correlates with fragility, no consistent correlation is found for the microscopic energy barriers. Instead, the latter shows a strong correlation with an independently computed structure dynamics measure obtained from isoconfigurational ensemble. Surprisingly, the two systems with the highest structure dynamics correlation, LJ at rho = 1.1 and the (8, 5) model, are respectively the least and most fragile within their classes. These systems exhibit broad mobility distributions, bimodal displacement profiles, and high non-Gaussian parameters, all indicative of dynamic heterogeneity. However, their dynamic susceptibilities remain low, suggesting a decoupling between spatial correlation and temporal heterogeneity. Both systems lie in the enthalpy-dominated regime and are near the spinodal, suggesting mechanical instability as a source of heterogeneity. These findings challenge the conventional linkage among fragility, heterogeneity, and structure-dynamics correlation.