论文标题
在弱耦合处,单验交换功能重新归一化组应用于二维Hubbard模型
Single-boson exchange functional renormalization group application to the two-dimensional Hubbard model at weak coupling
论文作者
论文摘要
我们通过将其应用于方形晶格上的二维Hubbard模型来说明单环功能性重归于(FRG)的最近引入的单环官能重归其化组(FRG)的算法优势。我们通过在半填充和有限的掺杂剂量以温度和相互作用强度研究,对Yukawa耦合的Fermion-Boson耦合以及相应的物理敏感性进行了详细分析。与传统的费米子FRG分解的比较表明,与传统FRG的剩余功能相反,SBE算法的其余功能描述了SBE过程以外的相关效应,在SBE过程以外的相关效应中起着可忽略的作用。值得注意的是,它们在伪临界过渡中也保持有限,而常规FRG实施的相应休息功能也有所不同。结果,FRG流的SBE公式可以大大减少两粒子顶点函数的数值努力,从而铺平了有希望的将来的多群和多旋转扩展的途径。
We illustrate the algorithmic advantages of the recently introduced single-boson exchange (SBE) formulation for the one-loop functional renormalization group (fRG), by applying it to the two-dimensional Hubbard model on a square lattice. We present a detailed analysis of the fermion-boson Yukawa couplings and of the corresponding physical susceptibilities by studying their evolution with temperature and interaction strength, both at half filling and finite doping. The comparison with the conventional fermionic fRG decomposition shows that the rest functions of the SBE algorithm, which describe correlation effects beyond the SBE processes, play a negligible role in the weak-coupling regime above the pseudo-critical temperature, in contrast to the rest functions of the conventional fRG. Remarkably, they remain finite also at the pseudo-critical transition, whereas the corresponding rest functions of the conventional fRG implementation diverge. As a result, the SBE formulation of the fRG flow allows for a substantial reduction of the numerical effort in the treatment of the two-particle vertex function, paving a promising route for future multiboson and multiloop extensions.