Quantum Field Theories in the Infinite-Momentum Frame III. Quantization of Coupled Spin-One Fields

Light-front quantization of spin-one fields coupled to a conserved or nonconserved current constructed from a Dirac field is studied. It is shown that an operator phase transformation must be performed on the Dirac field in order to maintain simple canonical commutation relations and a simple Hamiltonian. In this formulation quantum electrodynamics emerges as the zero-mass limit of the massive gluon model. Lorentz invariance of the vector-gluon model is explicitly verified. Vacuum expectation values of operator products and Green's functions are studied and spectral sum rules are derived. The general structure of the current commutators on a light front is formally not altered by the interactions. Feynman's parton model for deep-inelastic electron scattering is derived from canonical light-front current commutation relations. The structure function in the Bjorken scaling limit is related to the $p^{+}$ distribution of the constituents of the hadron target in any frame of reference.