Truncated-unity parquet equations: Application to the repulsive Hubbard model
Truncated-unity parquet equations: Application to the repulsive Hubbard model
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DOI：
10.1103/physrevb.98.075143
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发表时间：
2018-08-24
影响因子：
3.7
通讯作者：
Honerkamp, C.
中科院分区：
文献类型：
--
作者：
Eckhardt, C. J.;Schober, G. A. H.;Honerkamp, C.
Parquet方程是一组自洽的方程，用于描述相互作用的多费米子系统的有效两粒子顶点。然而，由于顶点的复杂的涌现动量和频率结构，将这些方程应用于体模型是苛刻的。在这里，我们展示了如何通过截断的统一，这是在功能重整化群的背景下开发的有效地处理动量依赖的通道分解，可以转移到镶木地板方程。这导致了显着降低的复杂性和内存消耗缩放仅与离散动量的数量线性。我们应用这种技术的半填充排斥哈伯德模型的正方形晶格和通道投影顶点和全可约顶点的近似解。
The parquet equations are a self-consistent set of equations for the effective two-particle vertex of an interacting many-fermion system. The application of these equations to bulk models is, however, demanding due to the complex emergent momentum and frequency structure of the vertex. Here, we show how a channel decomposition by means of truncated unities, which was developed in the context of the functional renormalization group to efficiently treat the momentum dependence, can be transferred to the parquet equations. This leads to a significantly reduced complexity and memory consumption scaling only linearly with the number of discrete momenta. We apply this technique to the half-filled repulsive Hubbard model on the square lattice and present approximate solutions for the channel-projected vertices and the full reducible vertex.