Andreev Peaks and Massive Magnons in Cuprate SNS junctions

The projected SO(5) theory (pSO(5)) is used to resolve the puzzle of two distinct energy gaps in high T${}_c$ Superconductor-Normal-Superconductor junctions. Counter to conventional theory of multiple Andreev reflections (MAR), the differential resistance peaks are associated with the antiferromagnetic resonance observed in neutron scattering, and not with Cooper pair breaking. The pSO(5) and MAR theories differ by the expected tunneling charges at the peaks. We propose that shot noise experiments could discriminate against the conventional interpretation.