The theory of the superconductivity mediated by kinematic and exchange interactions in t?J and two-band Hubbard models in a paramagnetic state is formulated. The Dyson equations for the matrix Green functions in terms of the Hubbard operators are obtained in the non-crossing approximation. To calculate superconducting T c a numerical solution of self-consistent Eliashberg equations is proposed.

Based on the variational Gutzwiller theory, we present a method for the computation of response functions for multiband Hubbard models with general local Coulomb interactions. The improvement over the conventional random-phase approximation is exemplified for an infinite-dimensional two-band Hubbard model where the incorporation of the local multiplet structure leads to a much larger sensitivit...

The combination of bandstructure theory in the local density approximation with dynamical mean field theory was recently successfully applied to V2O3 – a material which undergoes the famous Mott-Hubbard metal-insulator transition upon Cr doping. The aim of this short paper is to emphasize two aspects of our recent results: (i) the filling of the Mott-Hubbard gap with increasing temperature, and...

A microscopic theory of superconducting pairing within the Hubbard model is discussed. A Dyson equation for the matrix thermodynamic Green function in the Nambu representation for Hubbard operators is derived by applying the Mori-type projection technique for the equation of motion method. The self-energy is calculated in the noncrossing approximation for electron scattering on spin and charge ...