Nonperturbative solution of scalar Yukawa model in two- and three-body   Fock space truncations
  The Light-Front Tamm-Dancoff method of finding the nonperturbative solutions in field theory is based on the Fock decomposition of the state vector, complemented with the sector-dependent nonperturbative renormalization scheme. We show in detail how to implement the renormalization procedure and to solve the simplest nontrivial example of the scalar Yukawa model in the two- and three-body Fock space truncations incorporating scalar "nucleon" and one or two scalar "pions". 
Vladimir A. Karmanov, Yang Li, Alexander V. Smirnov, and James P. Vary
hep-th nucl-th