Role of strong correlation in the recent angle-resolved photoemission spectroscopy experiments on cuprate superconductors

Motivated by recent photoemission experiments on cuprates, the low-lying excitations of a strongly correlated superconducting state are studied numerically. It is observed that along the nodal direction these low-lying one-particle excitations show a linear momentum dependence for a wide range of excitation energies and, thus, they do not present a kink-like structure. The nodal Fermi velocity vF, as well as other observables, are systematically evaluated directly from the calculated dispersions, and they are found to compare well with experiments. It is argued that the parameter dependence of vF is quantitatively explained by a simple picture of a renormalized Fermi velocity.