Z(2)-slave-spin theory for strongly correlated fermions

Article

关键词: FUNCTIONAL-INTEGRAL APPROACH;    MEAN-FIELD THEORY;    SLAVE-BOSON APPROACH;    HUBBARD-MODEL;    MOTT TRANSITION;    GUTZWILLER APPROXIMATION;    GAUGE-THEORY;    INSULATOR-TRANSITION;    SYSTEMS;    PHYSICS;   

DOI  :  10.1103/PhysRevB.81.155118

来源: SCIE

【 摘 要 】

We review a representation of Hubbard-like models that is based on auxiliary pseudospin variables. These pseudospins refer to the local charge modulo two in the original model and display a local Z(2) gauge freedom. We discuss the associated mean-field theory in a variety of different contexts which are related to the problem of the interaction-driven metal-insulator transition at half-filling including Fermi surface deformation and spectral features beyond the local approximation. Notably, on the mean-field level, the Hubbard bands are derived from the excitations of an Ising model in a transverse field and the quantum critical point of this model is identified with the Brinkman-Rice criticality of the almost localized Fermi liquid state. Nonlocal correlations are included using a cluster mean-field approximation and the Schwinger boson theory for the auxiliary quantum Ising model.

【 授权许可】

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