LAUSR

Significance We investigate the pairing glue of superconductivity in the two-dimensional Hubbard model, for interaction values relevant to cuprate physics, within a nonperturbative and unbiased approach. In a generalized fluctuation diagnostics scheme applied to the ordered superconducting state, we analyze the self-energies and scattering amplitudes computed by means of cluster dynamical mean-field theory below the critical temperature of superconductivity. Independent of the doping level, we rigorously identify antiferromagnetic fluctuations as the dominant mechanism driving the unconventional d-wave superconducting phase. These fluctuations are of a different nature from those considered in traditional spin fluctuation approximations.