We present an intuitive, light front reduction scheme for the Bethe-Salpeterequation that consists of iterations of the (light front) energy dependentcovariant equation followed by an instantaneous approximation. This scheme isequivalent to and motivates the form of a standard reduction that reproduceslight front, time ordered perturbation theory for bound states. We use thisthree-dimensional light front formalism to compute electromagnetic form factorsbetween bound states to show how higher, light front Fock components arise fromthe covariant Bethe-Salpeter wave function. Moreover, we show that non-wavefunction vertices, which arise after integration over the minus momenta, arecompletely removed in favor of higher Fock states when one correctly takes intoaccount all contributions at a given order in perturbation theory. Suchnon-wave function vertices are shown only to occur in models in which theinteractions are instantaneous. These models lack true higher Fock states. Thenormalization of the reduced wave function is derived from the covariantframework and related to nonvalence probabilities using familiar Fock spaceprojection operators. Using a simple model, we obtain expressions forgeneralized parton distributions that are continuous. The nonvanishing of thesedistributions at the crossover between kinematic regimes (where the pluscomponent of the struck quark's momentum is equal to the plus component of themomentum transfer) is tied to higher Fock components. Lastly we apply the lightfront reduction to timelike form factors and derive expressions for thegeneralized distribution amplitudes in this model.
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