论文标题
简单而简单的镶木近似值：二维Hubbard模型中的单玻色子交换
The plain and simple parquet approximation: single- and multi-boson exchange in the two-dimensional Hubbard model
论文作者
论文摘要
顶点校正的镶木式方法是公正的，但在计算上要求。因此，大多数应用程序仅限于小集群大小或依赖各种简化的近似值。我们最近表明，镶木木图的琼脂化提供了与原始纯粹的费米子配方相比的解释性和算法优势。在这里，我们通过将该方法应用于弱耦合时的正方形晶格上的半填充哈伯德模型来介绍该方法的数值实现的第一个结果。改进的算法性能使我们能够评估$ 16 \ times16 $晶格的镶木近似，从而保留了各种顶点函数的全部动量和频率结构。我们讨论它们的对称性，并使用截断的统一近似来考虑其动量依赖性的参数化。
The parquet approach to vertex corrections is unbiased but computationally demanding. Most applications are therefore restricted to small cluster sizes or rely on various simplifying approximations. We have recently shown that the bosonization of the parquet diagrams provides interpretative and algorithmic advantages over the original purely fermionic formulation. Here we present first results of the numerical implementation of this method by applying it to the half-filled Hubbard model on the square lattice at weak coupling. The improved algorithmic performance allows us to evaluate the parquet approximation for a $16\times16$ lattice, retaining the full momentum and frequency structure of the various vertex functions. We discuss their symmetries and consider parametrizations of their momentum dependence using the truncated unity approximation.
