Theoretical determination of the superconducting phase of UPt3

We show that recent measurements of the dynamical susceptibility of UPt3 by Goldman et al. [Phys. Rev. B 36, 8523 (1987)] are sufficient to determine the superconducting phase of UPt3 unambiguously within the picture of spin-fluctuation-mediated pairing. The gap function belongs to the two-dimensional E1 representation and has complex coefficients, thus breaking time-reversal symmetry. It has a line of nodes in the energy gap in the basal plane and point nodes at the poles of the Fermi surface