论文标题
完整的配置相互作用量子蒙特卡洛，用于耦合电子 - 玻色子系统和无限空间
Full configuration interaction quantum Monte Carlo for coupled electron--boson systems and infinite spaces
论文作者
论文摘要
我们扩展了全构型相互作用量子蒙特卡洛（FCIQMC）的范围，用于将其用于耦合的fermion-boson汉密尔顿人，从而减轻了玻色子占用的先验截断，这对于许多其他波浪函数的方法是必不可少的。详细说明所需的算法更改以产生有效的激发，我们将FCIQMC应用于两个对比设置。首先是无标志性的哈伯德 - 局部电子 - phonon相互作用模型，在这里，我们表明，通过重要性采样和/或重新升级，该方法可以通过对人口偏见进行控制，该方法可以实现无偏向热力学限制的无偏见，而无需遭受额外的计算孔的良好的孔隙孔孔的额外的计算，而无需遭受额外的计算。其次，我们将该方法应用于量子嵌入方案中的“求解器”，该方案将电子系统映射到局部电子玻璃辅助模型，玻色子代表耦合到远距离等离子类似的波动。尽管有正式的符号问题，我们还可以轻松地品尝这些通用电子 - 波森汉密尔顿人，包括忠实地重建系统的密度矩阵。
We extend the scope of full configuration interaction quantum Monte Carlo (FCIQMC) to be applied to coupled fermion-boson hamiltonians, alleviating the a priori truncation in boson occupation which is necessary for many other wave function based approaches to be tractable. Detailing the required algorithmic changes for efficient excitation generation, we apply FCIQMC in two contrasting settings. The first is a sign-problem-free Hubbard--Holstein model of local electron-phonon interactions, where we show that with care to control for population bias via importance sampling and/or reweighting, the method can achieve unbiased energies extrapolated to the thermodynamic limit, without suffering additional computational overheads from relaxing boson occupation constraints. Secondly, we apply the method as a `solver' within a quantum embedding scheme which maps electronic systems to local electron-boson auxiliary models, with the bosons representing coupling to long-range plasmonic-like fluctuations. We are able to sample these general electron-boson hamiltonians with ease despite a formal sign problem, including a faithful reconstruction of converged reduced density matrices of the system.
