Electron-phonon system with strong electronic correlations

The properties of the Hubbard-Holstein model for an electron-phonon system with strong electron correlations are investigated on the basis of a new diagram technique. The equations of the main dynamical quantities and optical dispersionless phonons are established. The problem of excluding partially or completely the phonon's coordinates and the corresponding renormalization of the physical parameters of the theory is discussed.Published in Teoreticheskaya i Matematicheskaya Fizika, Vol. 103, No. 1, pp. 138–160, April, 1995.