Kinematic mechanism of the modulation of the spectral intensity in the spatially uniform system of Hubbard fermions

Using the exact representation of the Green's function constructed in terms of the Hubbard operators, it has been shown that the kinematic interaction that induces the spin-fluctuation processes in the spatially uniform system of Hubbard fermions leads to significant variations in the spectral intensity $A(\mathbf{k},\omega)$ in the Brillouin zone. As a result, the modulation of $A(\mathbf{k},\omega)$ appears in the Fermi contour. The sign of the hopping integral within the first coordination sphere is determined by the contour section, where $A(\mathbf{k},\omega)$ decreases according to the angle-resolved photoemission spectroscopy data.