论文标题
克服表面跳跃中密度矩阵的阳性违规行为
Overcoming positivity violations for density matrices in surface hopping
论文作者
论文摘要
最少的切换表面跳跃（FSSH）已成为建模分子系统量子动力学的主要方法之一。虽然其原始配方仅限于绝热种群，但对FSSH在相干现象中的应用越来越兴趣促使人们应该基于FSSH轨迹构建一个完整的密度矩阵的问题。一种直接的解决方案是根据波函数系数定义绝热相干。在本文中，我们证明了通过这种处理在密度基质中引入的不一致可能导致侵犯阳性。我们进一步表明，最近提出的FSSH的相干概括导致密度矩阵满足阳性，同时在参数空间的大量（但不是全部）中产生了提高的精度。
Fewest-switches surface hopping (FSSH) has emerged as one of the leading methods for modeling the quantum dynamics of molecular systems. While its original formulation was limited to adiabatic populations, the growing interest in the application of FSSH to coherent phenomena prompts the question how one should construct a complete density matrix based on FSSH trajectories. A straightforward solution is to define adiabatic coherences based on wavefunction coefficients. In this Paper, we demonstrate that inconsistencies introduced in the density matrix through such treatment may lead to a violation of positivity. We furthermore show that a recently proposed coherent generalization of FSSH results in density matrices that satisfy positivity, while yielding an improved accuracy throughout much (but not all) of parameter space.
