We investigate the Josephson coupling between two superconductors mediated
through an infinite U Anderson impurity, adapting a variational wavefunction
approach which has proved successful for the Kondo model. Unlike the Kondo
problem, however, a crossing of singlet and doublet state energies may be
produced by varying the ratio of Kondo energy to superconducting gap, in
agreement with recent work of Clerk and Ambegaokar. We construct the phase
diagram for the junction and discuss properties of different phases. In
addition, we find the singlet and doublet state energies within a slave boson
mean field approach. We find the slave boson mean field treatment is unable to
account for the level crossing.Comment: 5 pages; 4 encapsulated PostScript figures; submitted to Phys. Rev.