Relativistic variables for covariant, retardless wave equations

TL;DR

This paper reformulates a reduced Dirac equation in a covariant form applicable to any reference frame using specific momentum variables, maintaining consistency with retardless interaction models.

Contribution

It introduces a covariant formulation of a reduced Dirac equation using new momentum variables, extending previous work beyond the Center of Mass frame.

Findings

Covariant form of the reduced Dirac equation derived.

Momentum variables compatible with retardless interactions identified.

Equation applicable in generic reference frames.

Abstract

A reduced form of the Dirac equation has been previously introduced and studied in the Center of Mass reference frame. In this work we show that this equation can be written in a covariant form in a generic reference frame by using specific momentum variables. These variables are also consistent with the retardless form of the interaction of the model.