论文标题
将微观动力学的粗粒化成介观瞬态模型
Coarse-Graining of Microscopic Dynamics into Mesoscopic Transient Potential Model
论文作者
论文摘要
我们表明，合并瞬态电势的介观粗粒动力学模型可以正式得出来自基础微观动力学模型。作为微观动力学模型，我们采用了过度阻尼的langevin方程。通过利用路径概率和Onsager-Machlup型动作，我们计算了粗粒介质自由度的路径概率。可以通过纳入瞬态潜力来简化介观自由度的作用。然后可以简单地用瞬态电势（LETP）来简单地描述介质自由度的动态方程。作为一个简单且可以分析的近似值，我们引入了表达瞬态潜力状态的其他自由度。然后，我们将系统的动力学大致表示为瞬态电位的LETP和动力学模型的组合。所得的动力学模型具有与响应性粒子动力学（快速）类型模型[W.的动力学结构相同的动力学结构[W. J. Briels，软物质5，4401（2009）]和多链滑动类型模型[T. Uneyama和Y. Masubuchi，J。Chem。物理。 137，154902（2012）]。作为演示，我们将粗粒方法与LETP应用于超冷液体中的单个粒子动力学，并将LETP的结果与分子动力学模拟和其他粗粒模型进行比较。
We show that a mesoscopic coarse-grained dynamics model which incorporates the transient potential can be formally derived from an underlying microscopic dynamics model. As a microscopic dynamics model, we employ the overdamped Langevin equation. By utilizing the path probability and the Onsager-Machlup type action, we calculate the path probability for the coarse-grained mesoscopic degrees of freedom. The action for the mesoscopic degrees of freedom can be simplified by incorporating the transient potential. Then the dynamic equation for the mesoscopic degrees of freedom can be simply described by the Langevin equation with the transient potential (LETP). As a simple and analytically tractable approximation, we introduce additional degrees of freedom which express the state of the transient potential. Then we approximately express the dynamics of the system as the the combination of the LETP and the dynamics model for the transient potential. The resulting dynamics model has the same dynamical structure as the responsive particle dynamics (RaPiD) type models [W. J. Briels, Soft Matter 5, 4401 (2009)] and the multi-chain slip-spring type models [T. Uneyama and Y. Masubuchi, J. Chem. Phys. 137, 154902 (2012)]. As a demonstration, we apply our coarse-graining method with the LETP to a single particle dynamics in a supercooled liquid, and compare the results of the LETP with the molecular dynamics simulations and other coarse-graining models.
