Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland.
J Chem Phys. 2020 Dec 21;153(23):234106. doi: 10.1063/5.0019687.
Thermally driven processes of molecular systems include transitions of energy barriers on the microsecond timescales and higher. Sufficient sampling of such processes with molecular dynamics simulations is challenging and often requires accelerating slow transitions using external biasing potentials. Different dynamic reweighting algorithms have been proposed in the past few years to recover the unbiased kinetics from biased systems. However, it remains an open question if and how these dynamic reweighting approaches are connected. In this work, we establish the link between the two main reweighting types, i.e., path-based and energy-based reweighting. We derive a path-based correction factor for the energy-based dynamic histogram analysis method, thus connecting the previously separate reweighting types. We show that the correction factor can be used to combine the advantages of path-based and energy-based reweighting algorithms: it is integrator independent, more robust, and at the same time able to reweight time-dependent biases. We can furthermore demonstrate the relationship between two independently derived path-based reweighting algorithms. Our theoretical findings are verified on a one-dimensional four-well system. By connecting different dynamic reweighting algorithms, this work helps to clarify the strengths and limitations of the different methods and enables a more robust usage of the combined types.
分子系统的热驱动过程包括微秒时间尺度及更高时间尺度上的能量势垒跃迁。使用分子动力学模拟充分采样这些过程具有挑战性，通常需要使用外部偏置势来加速缓慢的跃迁。过去几年已经提出了不同的动态重加权算法，以从有偏系统中恢复无偏动力学。然而，这些动态重加权方法是否以及如何相关仍然是一个悬而未决的问题。在这项工作中，我们建立了两种主要的重加权类型（基于路径和基于能量的重加权）之间的联系。我们为基于能量的动态直方图分析方法推导出了基于路径的校正因子，从而将以前独立的重加权类型联系起来。我们表明，该校正因子可用于结合基于路径和基于能量的重加权算法的优点：它与积分器无关，更稳健，同时能够重新加权时变偏差。我们还可以证明两种独立推导的基于路径的重加权算法之间的关系。我们的理论发现通过一维四势阱系统得到了验证。通过连接不同的动态重加权算法，这项工作有助于澄清不同方法的优缺点，并能够更稳健地使用组合类型。
