Hund’s rule theory for heavy fermion superconductors

In this paper, a multiorbital generalization of standard spin fluctuation theory is considered within an on-site approximation. For f electrons, this theory leads to an instability for a superconducting pair state which obeys Hund's rules, with L=5, S=1, and J=4. The degeneracy of this state is broken by crystalline effects, and realistic calculations for UPt₃ find a pair state with Γ₆^- (E₂ᵤ) symmetry, consistent with current experimental constraints.