论文标题
镶木近似和一环重新归一化组：领先阶层的等效性
Parquet approximation and one-loop renormalization group: Equivalence on the leading-logarithmic level
论文作者
论文摘要
我们研究了模型的两粒子顶点功能的功能重新归一化组（FRG）流动，以用于金属中的X射线吸收。关于对数差异的出现，该模型对于重要的零和一维系统的重要类是典型的，该系统包括Kondo模型和相互作用的一维费米气体。在我们的分析中，我们在实时零温度形式主义的框架中制定了FRG，在该框架之前，以基于镶木质的方法研究了模型。我们确定，在详细的水平上，一个完全制作的，纯粹的纯粹的单环FRG近似是完全等效的。因此，发现这两个近似方案仅代表相同技术步骤的不同观点。这一发现还重新确认了对此类模型的一环RG近似能力的传统理解，最近通过对Multiloop FRG对X射线吸收模型进行了调查，这对此受到了质疑。
We investigate the functional renormalization group (FRG) flow of the two-particle vertex function of a model for X-ray absorption in metals. Concerning the appearance of logarithmic divergences, the model is prototypical for an important class of mostly zero- and one-dimensional systems which includes the Kondo model and the interacting one-dimensional Fermi gas. For our analysis we formulate the FRG in the framework of the real-time zero-temperature formalism, in which the model was studied before with a parquet-based approach. We establish that a reasonably crafted, purely-fermionic one-loop FRG approximation is fully equivalent on a detailed level to the leading-logarithmic parquet approximation. These two approximation schemes are thus found to just represent different perspectives on the same technical steps. This finding also reconfirms the traditional understanding of the capabilities of one-loop RG approximations for such models, which was recently put into question by an investigation of the X-ray-absorption model with multiloop FRG.
