Schr\"odinger Models for Solutions of the Bethe-Salpeter Equation in   Minkowski Space. II. Fermionic Bound-State Constituents
  In view of the obstacles encountered in any attempts to solve the Minkowski-space Bethe-Salpeter equation for bound states of two fermions, we study the possibility to model the bound-state features, at least at a qualitative level, by a Schr\"odinger description. Such a nonrelativistic potential model can be constructed by applying, to any given Bethe-Salpeter spectral data, "geometric spectral inversion" in its recently extended form, which tolerates also singular potentials. This leads to the adaptation of explicit models that provide an overview accounting for the Bethe-Salpeter formalism's complexities. 
Richard L. Hall, Wolfgang Lucha
math-ph hep-ph hep-th math.MP quant-ph