arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1909.03589cond-mat.stat-mechphysics.chem-ph
收藏

非平衡分子动力学模拟中增强采样的变分控制力

Variational control forces for enhanced sampling of nonequilibrium molecular dynamics simulations

Avishek Das, David T. Limmer

摘要:

我们引入了一个变分算法来估计一个罕见的事件在非平衡分子动力学模拟的可能性,通过评估的最佳控制力。在选定的基础内的控制力的优化是可能的显式形式的成本函数的梯度在驱动轨迹的变化参数的变化的敏感性。我们认为概率的时间积分动态观测的特点是其大偏差函数,并发现在许多情况下,变分估计是定量准确的。此外,我们提供的表达式,以准确地纠正变分估计,可以直接评估。我们基准此算法对数值精确解的驱动粒子在周期性的潜力,其中的控制力可以表示与一个完整的基础模型。然后,我们证明了该算法的效用在一条线上的排斥粒子的模型,它经历了一个动态的相变,导致奇异变化的形式的最佳控制力。在这两个系统中,我们发现快速收敛,并能够评估大偏差函数的统计效率显着增加替代蒙特卡罗方法。

英文摘要:

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.

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。

↑