NEW FUNCTIONAL INTEGRAL APPROACH TO STRONGLY CORRELATED FERMI SYSTEMS - THE GUTZWILLER APPROXIMATION AS A SADDLE-POINT
NEW FUNCTIONAL INTEGRAL APPROACH TO STRONGLY CORRELATED FERMI SYSTEMS - THE GUTZWILLER APPROXIMATION AS A SADDLE-POINT
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DOI：
10.1103/physrevlett.57.1362
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发表时间：
1986-09-15
影响因子：
8.6
通讯作者：
RUCKENSTEIN, AE
中科院分区：
文献类型：
--
作者：
KOTLIAR, G;RUCKENSTEIN, AE
我们提出了格子费米子的Hubbarda和Anderson模型的一个新的泛函积分表示。在零温度下，最简单的鞍点近似导致了从古兹威尔变分波函数得到的结果。这种方法揭示了古兹威尔近似的局限性，并阐明了它与安德森模型的“辅助玻色子”平均场理论的联系。这一表述导致了一种新的强耦合平均场理论，该理论允许统一处理反铁磁性和铁磁性、金属到绝缘体的转变和近藤补偿效应。
We propose a new functional integral representation of the Hubbarda and Anderson models of lattice fermions. The simplest saddle-point approximation leads, at zero temperature, to the results derived from the Gutzwiller variational wave function. This approach uncovers the limitations of the Gutzwiller approximation and clarifies its connection to the" auxiliary-boson" mean-field theory of the Anderson model. This formulation leads to a novel strong-coupling mean-field theory which allows for a unified treatment of antiferromagnetism and ferromagnetism, metal-to-insulator transition, and Kondo compensation effects.