论文标题
在弱耦合时，哈伯德模型中淋巴结/抗邻近二分法的波动诊断：镶木双效率
Fluctuation diagnostic of the nodal/antinodal dichotomy in the Hubbard model at weak coupling: a parquet dual fermion approach
论文作者
论文摘要
我们将Boson Exchange Parquet求解器应用于在小相互作用时在平方晶格上的半充满Hubbard模型。我们的结果表明，在这种制度中，非局部顶点校正在伪PSEUDOGAP的形成中起着重要作用。也就是说，与简单的梯子近似相比，镶木quet方程中包含的这些其他顶点校正增强了自旋波动与准粒子的耦合。因此，伪群已经在更高温度下打开，与数值精确的示意蒙特卡洛的定量一致。用玻色子交换来表示镶木木图的表示有助于较大的晶格大小，并引起了自我能源的无偏波诊断，这不依赖于Fierz的歧义。波动的诊断意味着淋巴结和抗衰变的费物受到旋转波动的同等影响，并具有确切的相应嵌套向量$（π，π）$。然而，与节点相比，抗鼻夫妇更有效地效率为不均质的波动，从而导致淋巴结/抗邻近二分法。我们从类似自旋的特性计算来证实了这一发现。
We apply the boson exchange parquet solver for dual fermions to the half-filled Hubbard model on a square lattice at small interaction. Our results establish that, in this regime, nonlocal vertex corrections play an important role in the formation of the pseudogap. Namely, in comparison to the simpler ladder approximation, these additional vertex corrections included in the parquet equations enhance the coupling of spin fluctuations with the quasiparticles. The pseudogap thus opens already at a higher temperature, in quantitative agreement with the numerically exact diagrammatic Monte Carlo. The representation of the parquet diagrams in terms of boson exchange facilitates large lattice sizes and gives rise to an unbiased fluctuation diagnostic of the self-energy, which does not rely on the Fierz ambiguity. The fluctuation diagnostic implies that nodal and antinodal fermions are affected equally by spin fluctuations with the exact commensurate nesting vector $(π,π)$. However, the antinode couples more efficiently to incommensurate fluctuations than the node, leading to the nodal/antinodal dichotomy. We corroborate this finding in terms of a spin-fermion-like calculation.
