论文标题
相互作用的晶格系统中的单粒子和两粒子有限尺寸效应
Single- and two-particle finite size effects in interacting lattice systems
论文作者
论文摘要
扩展量子系统的模拟通常是通过将有限系统大小的仿真序列推断为热力学极限的。在量子蒙特卡洛群落中，扭曲平衡是一种有效的策略，以消除一身有限尺寸的效果。在动态平均场群落中，将动态平均场理论的聚类概括用于研究非本地相关性的系统。在这项工作中，我们将动态平均场理论的扭曲平均值和动态群集近似变体放在平等的基础上，讨论共同点和差异，并将两种技术的结果与标准的周期性边界技术进行比较。在具有局部，短距离和Yukawa的长距离相互作用的Hubbard型模型的示例中，我们表明所有方法都会收敛到相同的极限，但是在实践中，收敛速度有所不同。我们表明，嵌入理论是管理一体和两体有限尺寸效应的有效工具，特别是如果相互作用在扭转角上平均。
Simulations of extended quantum systems are typically performed by extrapolating results of a sequence of finite-system-size simulations to the thermodynamic limit. In the quantum Monte Carlo community, twist-averaging was pioneered as an efficient strategy to eliminate one-body finite size effects. In the dynamical mean field community, cluster generalizations of the dynamical mean field theory were formulated to study systems with non-local correlations. In this work, we put the twist-averaging and the dynamical cluster approximation variant of the dynamical mean field theory onto equal footing, discuss commonalities and differences, and compare results from both techniques to the standard periodic boundary technique. At the example of Hubbard-type models with local, short-range and Yukawa-like longer range interactions we show that all methods converge to the same limit, but that the convergence speed differs in practice. We show that embedding theories are an effective tool for managing both one-body and two-body finite size effects, in particular if interactions are averaged over twist angles.
