The diagrammatic theory for strongly correlated electron systems

Abstract

Solution of high-temperature superconductivity problem is closely connected with the construction of the theory of strongly correlated electron systems, which is now the central problem of condensed matter physics. The strong coupling diagram technique is an approach for investigating systems with moderate to strong electron correlations. V.A. Moskalenko and co-workers have developed a new approach in the theory of strongly correlated electrons, using the original diagram technique for the Hubbard model, the basic model of strongly correlated electron systems. They formulated a new version of the thermo-dynamic perturbation theory for these systems.