Distribution function of Hubbard quasiparticles in two-dimensional systems with inclusion of dynamic processes of spin-fluctuation scattering

Spin-fluctuation scattering in an ensemble of strongly correlated electrons in CuO₂ planes of high-temperature superconductors is investigated. It is demonstrated that this process significantly modifies the distribution function of Hubbard quasiparticles. The influence of spin-fluctuation scattering mathematically manifests itself in the appearance of the correction to the strength operator in the numerator of the single-fermion Green’s function dependent on the Matsubara frequency. This correction differently renormalizes the spectral intensity on different energy scales and determines the dependence of the Migdal discontinuity on the electron concentration in the system.