论文标题
在量子关键时的多通道Kondo模型的订单参数
Order parameter for the multichannel Kondo model at quantum criticality
论文作者
论文摘要
一个多通道的围绕模型，其中两个或多个等效但独立的电子通道竞争筛选自旋1/2杂质，显示了杂质旋转的过度补偿，从而导致各种热力学和运输特性中的非Fermi-liquid行为。但是，当通道对称性损坏时，可能在零温度下发生杂质量子相变。描述杂质量子相变的顺序参数的识别非常困难，因为它超出了传统的Landau-Ginzburg-Wilson理论。通过采用自然轨道重新归一化组方法，我们从电子通道中的杂质与电子之间的自旋相关性的角度研究了两通道和三通道近代模型。在这里，我们证明，通过将自旋相关比作为一个顺序参数引入我们可以表征由通道不对称驱动的杂质量子相变。 In particular, the universal critical exponents $β$ of the spin-correlation ratio and $ν$ of the correlation length are explicitly determined by finite-sizescaling analysis, namely, $β= 0.10(1), ν= 2.0(1)$, and $β= 0.10(1), ν= 2.5(1)$ for the two-channel and three-channel Kondo models, respectively.
A multichannel Kondo model, where two or more equivalent but independent channels of electrons compete to screen a spin-1/2 impurity, shows overcompensation of the impurity spin, leading to the non-Fermi-liquid behavior in various thermodynamic and transport properties. However, when the channel symmetry is broken, an impurity quantum phase transition can occur at zero temperature. Identification of an order parameter describing the impurity quantum phase transition is very difficult since it is beyond the conventional Landau-Ginzburg-Wilson theory. By employing the natural orbitals renormalization group method, we study both two-channel and threechannel Kondo models, from the perspective of spin correlation between the impurity and electrons in electronic channels. Here we demonstrate that by introducing the spin-correlation ratio as an order parameter we can characterize impurity quantum phase transitions driven by channel asymmetry. In particular, the universal critical exponents $β$ of the spin-correlation ratio and $ν$ of the correlation length are explicitly determined by finite-sizescaling analysis, namely, $β= 0.10(1), ν= 2.0(1)$, and $β= 0.10(1), ν= 2.5(1)$ for the two-channel and three-channel Kondo models, respectively.
