Ground states of the Wick-Cutkosky model using light-front dynamics
  We consider the ground state in a model with scalar nucleons and a meson using the formalism of light-front dynamics. Light-front potentials for two-nucleon bound states are calculated using two approaches. First, light-front time-ordered perturbation theory is used to calculate one- and two-meson-exchange potentials. These potentials give results that agree well with the ladder and ladder plus crossed box Bethe-Salpeter spectra. Secondly, approximations that incorporate non-perturbative physics are used to calculate alternative one-meson-exchange potentials. These non-perturbative potentials give better agreement with the spectra of the full non-perturbative ground-state calculation than the perturbative potentials. For lightly-bound states, all of the approaches appear to agree with each other. 
Jason R. Cooke and Gerald A. Miller