Old-fashioned perturbation theory is applied to a relativistic theory in a reference frame with infinite total momentum. It is found that many undesirable diagrams disappear. The contribution of the remaining diagrams is described by a new set of rules with properties intermediate between those of Feynman diagrams and old-fashioned diagrams, e.g., energy denominators become covariant, and Feynman parameters appear naturally. The new rules are used to derive some integral equations.

We construct Galilean-invariant theories (with Schr\"odinger equations) at infinite momentum that describe interacting relativistic systems. Classes of both first- and second-quantized theories are… Expand

A version of a relativistic Hamiltonian theory is developed in which the four-momentum of the spurion lies on the light cone. A new point of this scheme is a specific regularisation by which the… Expand

We suggest a possible algorithm to calculate one-loop n-point functions within a variant of light-front perturbation theory. The key ingredients are the covariant Passarino-Veltman scheme and a… Expand

Field theory in the infinite-momentum frame has a number of simplifying features: absence of vacuum-pair creation and a nonrelativistic analogy connected with the existence of a two-dimensional… Expand

A regularization of light-front field theory which does not make a distinction between transverse and longitudinal coordinates is proposed, similar to the regularization in the BPHZ scheme, which has some advantages that do not exist in covariant field theory.Expand

In this paper it is shown how to get, through the use of suitable commutation relations, sum rules for the renormalization ratios between bare and dressed coupling constants. The method is completely… Expand