A diagram technique for strongly interacting fermion systems. Oneand twoband Hubbard models
Abstract
The basic notions of a diagram method for the oneband Hubbard model, including Green functions, generalized Wick theorem and Dyson equation are discussed. The study of MottHubbard and superconducting transitions is based on a localized approximation for the irreducible twoparticle Green function. A similar technique is developed for the twoband Hubbard model which is more closely related to the structure of CuO2 planes of highTc superconductors and to find the criterion of metalinsulator transition.
 Publication:

Unknown
 Pub Date:
 July 1994
 Bibcode:
 1994dtsi.rept.....M
 Keywords:

 Dyson Theory;
 Fermions;
 Green'S Functions;
 High Temperature Superconductors;
 Mathematical Models;
 Metals;
 Perturbation Theory;
 Approximation;
 Electrical Insulation;
 Phase Transformations;
 Superconductivity;
 Transition Temperature;
 Atomic and Molecular Physics