Variational control forces for enhanced sampling of nonequilibrium molecular dynamics simulations.
Variational control forces for enhanced sampling of nonequilibrium molecular dynamics simulations.
复制标题
用于增强非平衡分子动力学模拟采样的变分控制力。
DOI：
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复制
发表时间：
2019
影响因子：
4.4
通讯作者：
David T. Limmer
中科院分区：
文献类型：
--
作者：
Avishek Das;David T. Limmer
我们引入一种变分算法，通过对最优控制力的评估来估计非平衡分子动力学模拟中罕见事件发生的可能性。根据被驱动轨迹对变化参数变化的敏感性，通过成本函数的梯度的显式形式，可以在选定的基础内优化控制力。我们考虑以大偏差函数为特征的时间积分动力学可观测量的概率，发现在许多情况下，变分估计是定量准确的。此外，我们还给出了精确修正可直接估计的变分估计的表达式。我们以周期势中受驱动粒子模型的数值精确解为基准来测试该算法，其中控制力可以用完整的基来表示。然后，我们在一条线上的排斥粒子模型中演示了该算法的实用性，该模型经历了动态相变，导致最优控制力的形式发生奇异变化。在这两个系统中，我们发现快速收敛，并且能够评估大偏差函数，与其他蒙特卡罗方法相比，在统计效率上有显著的提高。
We introduce a variational algorithm to estimate the likelihood of a rare event within a nonequilibrium molecular dynamics simulation through the evaluation of an optimal control force. Optimization of a control force within a chosen basis is made possible by explicit forms for the gradients of a cost function in terms of the susceptibility of driven trajectories to changes in variational parameters. We consider probabilities of time-integrated dynamical observables as characterized by their large deviation functions and find that in many cases, the variational estimate is quantitatively accurate. Additionally, we provide expressions to exactly correct the variational estimate that can be evaluated directly. We benchmark this algorithm against the numerically exact solution of a model of a driven particle in a periodic potential, where the control force can be represented with a complete basis. We then demonstrate the utility of the algorithm in a model of repulsive particles on a line, which undergo a dynamical phase transition, resulting in singular changes to the form of the optimal control force. In both systems, we find fast convergence and are able to evaluate large deviation functions with significant increases in statistical efficiency over alternative Monte Carlo approaches.
DOI：
10.1088/1742-5468/ab4801
发表时间：
2019
期刊：
Theory and Experiment
影响因子：
--
作者：
Dolezal J
通讯作者：
Dolezal J