论文标题
二维Hubbard模型的光学电导率：顶点校正，新出现的Galilean不变性和单位点动力场均值近似的准确性
Optical Conductivity of the two dimensional Hubbard model: vertex corrections, emergent Galilean invariance and the accuracy of the single-site dynamical mean field approximation
论文作者
论文摘要
我们计算零温度下的二维方晶格哈伯德模型的频率依赖性电导率，这是相互作用强度中密度到二阶的密度的函数，并将结果与以相同阶数计算的单位点动力学均值场理论的预测进行了比较。我们发现，尽管忽略了顶点校正，但单个位点动力学平均场近似对于大多数载体浓度产生了半定量准确的结果，但是对于该理论表现出出现的galilean不变性的几乎空或几乎填充的频段案例，质量失败。如果嵌套很重要，该理论也会在定性上变得非常不准确。
We compute the frequency dependent conductivity of the two dimensional square lattice Hubbard model at zero temperature as a function of density to second order in the interaction strength, and compare the results to the predictions of single-site dynamical mean field theory computed at the same order. We find that despite the neglect of vertex corrections, the single site dynamical mean field approximation produces semiquantitatively accurate results for most carrier concentrations, but fails qualitatively for the nearly empty or nearly filled band cases where the theory exhibits an emergent Galilean invariance. The theory also becomes qualitatively inaccurate very near half filling if nesting is important.
