Departments of Mathematics, Physics, and Chemistry, Duke University, Durham, North Carolina 27708, USA.
Beijing International Center for Mathematical Research, Peking University, Beijing 100871, People's Republic of China.
J Chem Phys. 2018 Feb 14;148(6):064110. doi: 10.1063/1.5005024.
To accelerate the thermal equilibrium sampling of multi-level quantum systems, the infinite swapping limit of a recently proposed multi-level ring polymer representation is investigated. In the infinite swapping limit, the ring polymer evolves according to an averaged Hamiltonian with respect to all possible surface index configurations of the ring polymer and thus connects the surface hopping approach to the mean-field path-integral molecular dynamics. A multiscale integrator for the infinite swapping limit is also proposed to enable efficient sampling based on the limiting dynamics. Numerical results demonstrate the huge improvement of sampling efficiency of the infinite swapping compared with the direct simulation of path-integral molecular dynamics with surface hopping.
为了加速多级量子系统的热平衡采样，研究了最近提出的多级环聚合物表示的无限交换极限。在无限交换极限下，环聚合物根据平均哈密顿量演化，相对于环聚合物的所有可能的表面指数配置，从而将表面跳跃方法与平均场路径积分分子动力学连接起来。还提出了无限交换极限的多尺度积分器，以便基于极限动力学实现有效的采样。数值结果表明，与直接进行表面跳跃的路径积分分子动力学模拟相比，无限交换极限的采样效率有了很大的提高。
