2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/21191Quantitative analysis of the Josephson effect is shown to provide direct information about phase fluctuations in the superconducting banks. Applying the analysis to the cuprates, substantial quantum fluctuations between d-wave and s-wave pairing are found at low temperatures. A phenomenological model of such fluctuations is introduced and solved in a self-consistent single-site approximation. The cuprate parameters are argued to lie close to an exotic superconductor phase with condensation of electron quadruplets.SuperconductivityStrongly Correlated Electronstext