论文标题
弱非线性极限的单参数老化
Single-parameter aging in the weakly nonlinear limit
论文作者
论文摘要
物理衰老处理由分子重排引起的随时间变化的缓慢变化。这与非结晶材料（如聚合物和无机玻璃）有关，无论是在生产还是随后的使用过程中。 1971年的Narayanaswamy理论描述了物理衰老 - 一种固有的非线性现象 - 在所谓的材料时间$ξ$上的线性卷积积分方面。一般认为，由此产生的“纳拉亚纳斯瓦米（TN）形式主义”可以很好地描述小型但仍高线的温度变化的物理衰老。 TN形式主义的最简单版本是单参数老化，根据该年龄率$dξ/dt $是监控属性的指数函数[T。 Hecksher等人，J。Chem。物理。 142，241103（2015）]。对于从热平衡开始的温度跃升，这导致了监视属性的一阶微分方程，涉及系统特定功能。本文分析表明，在温度变化中，该方程式对第一阶的解决方案在零阶解，$ r_0（t）$方面具有通用表达。二进制Lennard-Jones玻璃的数值数据以前探测势能，证实，在弱非线性限制中，该理论可预测衰老从$ r_0（t）$（通过波动 - 隔离定理是标准化的平衡势能 - 能量 - 能量 - 能量 - 远程 - 远离时间 - 运动功能）。
Physical aging deals with slow property changes over time caused by molecular rearrangements. This is relevant for non-crystalline materials like polymers and inorganic glasses, both in production and during subsequent use. The Narayanaswamy theory from 1971 describes physical aging - an inherently nonlinear phenomenon - in terms of a linear convolution integral over the so-called material time $ξ$. The resulting "Tool-Narayanaswamy (TN) formalism" is generally recognized to provide an excellent description of physical aging for small, but still highly nonlinear temperature variations. The simplest version of the TN formalism is single-parameter aging according to which the clock rate $dξ/dt$ is an exponential function of the property monitored [T. Hecksher et al., J. Chem. Phys. 142, 241103 (2015)]. For temperature jumps starting from thermal equilibrium, this leads to a first-order differential equation for property monitored, involving a system-specific function. The present paper shows analytically that the solution to this equation to first order in the temperature variation has a universal expression in terms of the zeroth-order solution, $R_0(t)$. Numerical data for a binary Lennard-Jones glass former probing the potential energy confirm that, in the weakly nonlinear limit, the theory predicts aging correctly from $R_0(t)$ (which by the fluctuation-dissipation theorem is the normalized equilibrium potential-energy time-autocorrelation function).
