IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
Department of Physics, University of Nevada, Reno, Nevada 89557, USA.
Phys Rev Lett. 2018 Oct 19;121(16):165301. doi: 10.1103/PhysRevLett.121.165301.
We introduce a diagrammatic Monte Carlo approach to angular momentum properties of quantum many-particle systems possessing a macroscopic number of degrees of freedom. The treatment is based on a diagrammatic expansion that merges the usual Feynman diagrams with the angular momentum diagrams known from atomic and nuclear structure theory, thereby incorporating the non-Abelian algebra inherent to quantum rotations. Our approach is applicable at arbitrary coupling, is free of systematic errors and of finite-size effects, and naturally provides access to the impurity Green function. We exemplify the technique by obtaining an all-coupling solution of the angulon model; however, the method is quite general and can be applied to a broad variety of systems in which particles exchange quantum angular momentum with their many-body environment.
我们引入了一种图表式蒙特卡罗方法，用于研究具有大量自由度的量子多粒子系统的角动量性质。该方法基于一种图表式展开，它将通常的费曼图与原子和核结构理论中已知的角动量图合并在一起，从而将量子旋转固有的非阿贝尔代数纳入其中。我们的方法适用于任意耦合，没有系统误差和有限尺寸效应，并且可以自然地获得杂质格林函数。我们通过获得角动子模型的全耦合解来说明该技术；然而，该方法非常通用，可以应用于粒子与其多体环境交换量子角动量的各种系统中。
