Laboratory of Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
J Chem Phys. 2019 Feb 21;150(7):071101. doi: 10.1063/1.5082596.
Simulating the nonadiabatic dynamics of condensed-phase systems continues to pose a significant challenge for quantum dynamics methods. Approaches based on sampling classical trajectories within the mapping formalism, such as the linearized semiclassical initial value representation (LSC-IVR), can be used to approximate quantum correlation functions in dissipative environments. Such semiclassical methods however commonly fail in quantitatively predicting the electronic-state populations in the long-time limit. Here we present a suggestion to minimize this difficulty by splitting the problem into two parts, one of which involves the identity and treating this operator by quantum-mechanical principles rather than with classical approximations. This strategy is applied to numerical simulations of spin-boson model systems, showing its potential to drastically improve the performance of LSC-IVR and related methods with no change in the equations of motion or the algorithm in general, but rather by simply using different functional forms of the observables.
模拟凝聚相系统的非绝热动力学仍然是量子动力学方法面临的重大挑战。基于在映射形式内对经典轨迹进行采样的方法，如线性化半经典初值表示（LSC-IVR），可用于在耗散环境中近似量子相关函数。然而，这种半经典方法通常无法在长时间限制内定量预测电子态的布居数。在这里，我们提出了一种建议，即将问题分成两部分来最小化这一困难，其中一部分涉及身份，并通过量子力学原理而不是经典近似来处理该算符。该策略应用于自旋-玻色子模型系统的数值模拟，表明其有可能极大地提高 LSC-IVR 和相关方法的性能，而无需改变运动方程或一般算法，而只需使用不同的可观测量的函数形式。
