Diffusion of a particle in the Gaussian random energy landscape: Einstein relation and analytical properties of average velocity and diffusivity as functions of driving force

相关扩散系数景观中的随机游走

Random walks in correlated diffusivity landscapes

本文研究了相关扩散系数景观中布朗但非高斯扩散的持续峰值现象，通过连续时间随机游走模型揭示峰值源于粒子轨迹的强时空相关性，并证明高阶时间相关性对峰值形成至关重要。

Diffusion of a particle in the spatially correlated exponential random energy landscape: transition from normal to anomalous diffusion

Diffusive transport of a particle in spatially correlated random energy landscape having exponential density of states has been considered. We exactly calculate the diffusivity in the nondispersive quasi-equilibrium transport regime and found that for slow decaying correlation functions the diffusivity becomes singular at some particular temperature higher than the temperature of the transition to the true non-equilibrium dispersive transport regime. It means that the diffusion becomes anomalous and does not follow the usual $\propto t^{1/2}$ law. In such situation the fully developed non-equi…

Investigation of the relation between local diffusivity and local inherent structures in the Kob-Andersen Lennard-Jones model

We analyze one thousand independent equilibrium trajectories of a system of 155 Lennard Jones particles to separate in a model-free approach the role of temperature and the role of the explored potential energy landscape basin depth in the particle dynamics. We show that the diffusion coefficient $D$ can be estimated as a sum over over contributions of the sampled basins, establishing a connection between thermodynamics and dynamics in the potential energy landscape framework. We provide evidence that the observed non-linearity in the relation between local diffusion and basin depth is respons…

过冷液体中的剪切诱导扩散率

Shear-induced diffusivity in supercooled liquids

针对过冷液体中剪切扩散率与剪切率呈线性关系的现象，基于含剪切的Smoluchowski方程推导出有效分子扩散率公式，其线性修正项与模拟及实验吻合，并发现扩散率增强与温度成反比、与零剪切粘度成正比。

Saddles in the energy landscape probed by supercooled liquids

We numerically investigate the supercooled dynamics of two simple model liquids exploiting the partition of the multi-dimension configuration space in basins of attraction of the stationary points (inherent saddles) of the potential energy surface. We find that the inherent saddles order and potential energy are well defined functions of the temperature T. Moreover, decreasing T, the saddle order vanishes at the same temperature (T_MCT) where the inverse diffusivity appears to diverge as a power law. This allows a topological interpretation of T_MCT: it marks the transition from a dynamics bet…

The relationship between fragility, configurational entropy and the potential energy landscape of glass forming liquids

Glass is a microscopically disordered, solid form of matter that results when a fluid is cooled or compressed in such a fashion that it does not crystallise. Almost all types of materials are capable of glass formation -- polymers, metal alloys, and molten salts, to name a few. Given such diversity, organising principles which systematise data concerning glass formation are invaluable. One such principle is the classification of glass formers according to their fragility\cite{fragility}. Fragility measures the rapidity with which a liquid's properties such as viscosity change as the glassy sta…