Berthier L, Biroli G, Bouchaud J-P, Kob W, Miyazaki K, Reichman D R
Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR 5587, Université Montpellier II and CNRS, 34095 Montpellier, France.
J Chem Phys. 2007 May 14;126(18):184504. doi: 10.1063/1.2721555.
We study in detail the predictions of various theoretical approaches, in particular, mode-coupling theory (MCT) and kinetically constrained models (KCMs), concerning the time, temperature, and wave vector dependence of multipoint correlation functions that quantify the strength of both induced and spontaneous dynamical fluctuations. We also discuss the precise predictions of MCT concerning the statistical ensemble and microscopic dynamics dependence of these multipoint correlation functions. These predictions are compared to simulations of model fragile and strong glass-forming liquids. Overall, MCT fares quite well in the fragile case, in particular, explaining the observed crucial role of the statistical ensemble and microscopic dynamics, while MCT predictions do not seem to hold in the strong case. KCMs provide a simplified framework for understanding how these multipoint correlation functions may encode dynamic correlations in glassy materials. However, our analysis highlights important unresolved questions concerning the application of KCMs to supercooled liquids.
我们详细研究了各种理论方法的预测，特别是模式耦合理论（MCT）和动力学受限模型（KCMs），这些预测涉及多点关联函数的时间、温度和波矢依赖性，这些函数量化了诱导和自发动态涨落的强度。我们还讨论了MCT关于这些多点关联函数的统计系综和微观动力学依赖性的精确预测。将这些预测与模型易碎和强玻璃形成液体的模拟结果进行了比较。总体而言，MCT在易碎情况下表现相当不错，特别是解释了观察到的统计系综和微观动力学的关键作用，而MCT的预测在强情况下似乎不成立。KCMs为理解这些多点关联函数如何编码玻璃态材料中的动态关联提供了一个简化框架。然而，我们的分析突出了关于KCMs应用于过冷液体的重要未解决问题。
