利用局部软度参数识别动力学非均质结构特征
Identifying structural signature of dynamical heterogeneity via the local softness parameter
摘要：
在最近的一项研究中，我们提出了一种新的测量液体结构的方法，即平均场囚禁势的软度，并表明它可以描述动力学的温度依赖性。在这项工作中，我们把这个参数通过一个严格的测试，并研究这个软参数之间的因果关系，在当地的水平和当地的动态。我们首先扩展了早期的研究来描述局部柔软度。我们找到了一个分布的柔软度值的分布具有相当强的温度依赖性。这表明该参数可以识别局部结构非均质性。然后，我们研究了寿命的软参数，并表明其寿命是连接到众所周知的笼结构的过冷液体。最后，我们的理论预测，当地的柔软度和当地的动态是因果关系的起始温度以下，有一个去耦之间的短期和长期的动态，从而允许静态描述的笼子。我们发现，在较低的温度下，结构的异质性增加，而且，结构成为一个更好的预测的动态，从而引起动态异质性。我们还发现，一个硬的，不动的区域的柔软度随着时间的推移而演变，并成为软，最终移动由于在附近的重排，确认了众所周知的促进作用。
英文摘要：
In a recent study by some of us, we have proposed a new measure of the structure of a liquid, the softness of the mean-field caging potential, and shown that it can describe the temperature dependence of the dynamics. In this work, we put this parameter through a stringent test and study the causal relationship between this softness parameter at the local level and the local dynamics. We first extend the earlier study to describe the local softness. We find a distribution of the softness value where the distribution has reasonably strong temperature dependence. This shows that the parameter can identify the local structural heterogeneity. We then study the lifetime of the softness parameter and show that its lifetime is connected to the well-known cage structure in the supercooled liquids. Finally, our theory predicts that the local softness and the local dynamics is causal below the onset temperature where there is a decoupling between the short and long time dynamics, thus allowing a static description of the cage. We find that at lower temperatures, the structural heterogeneity increases, and also, the structure becomes a better predictor of the dynamics, thus giving rise to dynamic heterogeneity. We also find that the softness of a hard, immobile region evolves with time and becomes soft and eventually mobile due to the rearrangements in the neighbourhood, confirming the well-known facilitation effect.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
