Investigation of Hubbard model at band half-population

In terms of the strong Coulomb electron repulsion at a lattice point and making use of the generating functional one studied the equations for the Green electron function proper energy part. The mentioned equations are characterized by the form close to that of the self-congruent Born approximation in the weak coupling theory terms. The numerical solution of the integral equations leads to the results compatible with the dynamic mean value field theory data. It is shown, on particular, that as the Coulomb repulsion is stepped up the three-peak structure of a quasi-particle spectrum is being replaced by the two-peak one and the metal-dielectric phase transition is observed. The mentioned method is applicable when studying other models of the strongly correlated systems