The role of electron-phonon coupling and the pairing symmetry in high-temperature superconductors

I will present some evidence for strong electron-phonon coupling in cuprates and its important role in the pairing mechanism. I will also demonstrate that the bulk gap (pairing) symmetry in the cuprate superconductors is not of d-wave, but of extended s-wave with eight line nodes, which is compatible with a pairing potential of onsite repulsion and inter-site attraction.  In terms of the extended s-wave symmetry, two-third experiments can be explained quantitatively, and one third experiments qualitatively. On the other hand, the d-wave scenario agrees with two third experiments qualitatively and is unable to explain one-third experiments.