论文标题
二维Hubbard模型中订单参数和临界温度的动态功能重新归一化组计算
Dynamical functional renormalization group computation of order parameters and critical temperatures in the two-dimensional Hubbard model
论文作者
论文摘要
我们通过中等排斥相互作用分析了抗铁磁性和配对的相互作用。耦合电荷，磁性和配对波动在自发对称性断裂的能量尺度以上的波动是通过功能重新归一化组流量来处理的，而在该量表以下的间隙和顺序的形成在平均场理论中得到处理。相互作用顶点和间隙功能的全频率依赖性被考虑。我们计算磁性和配对差距的功能是掺杂$ p $的函数，并与静态近似的结果进行比较。尽管有效相互作用和配对差距的频率依赖性很强，但仍证实了先前静态官能重新归一化组计算的重要物理结果。特别是，有一个相当大的兴奋剂制度，与Néel或不固定的抗铁磁性共存，并具有稳健的配对。磁性的临界温度被解释为伪群交叉温度。从超流相相位刚度计算kosterlitz-无尽的温度，我们在$（p，t）$相图中获得了一个以15％的孔掺杂为中心的$（p，t）$相图。
We analyze the interplay of antiferromagnetism and pairing in the two dimensional Hubbard model with a moderate repulsive interaction. Coupled charge, magnetic and pairing fluctuations above the energy scale of spontaneous symmetry breaking are treated by a functional renormalization group flow, while the formation of gaps and order below that scale is treated in mean-field theory. The full frequency dependences of interaction vertices and gap functions is taken into account. We compute the magnetic and pairing gap functions as a function of doping $p$ and compare with results from a static approximation. In spite of strong frequency dependences of the effective interactions and of the pairing gap, important physical results from previous static functional renormalization group calculations are confirmed. In particular, there is a sizable doping regime with robust pairing coexisting with Néel or incommensurate antiferromagnetism. The critical temperature for magnetic order is interpreted as pseudogap crossover temperature. Computing the Kosterlitz-Thouless temperature from the superfluid phase stiffness, we obtain a superconducting dome in the $(p,T)$ phase diagram centered around 15 percent hole doping.
