  The structure of the nucleon is studied variationally on the lattice by
maximizing the overlap between the nucleon and a trial function generated by an
interpolating field containing variational parameters. We examine the effect of
the spatial extent of smeared quark sources, the degree of gauge field
smearing, the positions of smeared quark sources, inclusion of lower Dirac
components and of diquark substructure. Exploratory calculations with quenched
Wilson fermions at a pion mass of 900 MeV achieved overlaps as high as 80%, and
there was no evidence of diquark substructure.
