We investigate in this work a recently proposed diagrammatic quantum Monte Carlo method --- the inchworm Monte Carlo method --- for open quantum systems. We establish its validity rigorously based on resummation of Dyson series. Moreover, we introduce an integro-differential equation formulation for open quantum systems, which illuminates the mathematical structure of the inchworm algorithm. This new formulation leads to an improvement of the inchworm algorithm by introducing classical deterministic time-integration schemes. The numerical method is validated by applications to the spin-boson model.

中文翻译：

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用于开放量子系统的 Inchworm Monte Carlo 方法

我们在这项工作中研究了最近提出的图解量子蒙特卡罗方法——英寸蠕虫蒙特卡罗方法——用于开放量子系统。我们在对戴森系列的总结的基础上，严格地建立了它的有效性。此外，我们为开放量子系统引入了一个积分微分方程公式，它阐明了英寸虫算法的数学结构。这种新公式通过引入经典的确定性时间积分方案，改进了 inchworm 算法。该数值方法通过对自旋玻色子模型的应用得到验证。