Extended Hamiltonian Formalism of the Pure Space-Like Axial Gauge Schwinger Model II

TL;DR

This paper develops an extended Hamiltonian formalism for quantizing pure space-like axial gauge fields, addressing residual gauge fields and infrared divergences, and providing a consistent operator solution for the Schwinger model.

Contribution

It introduces guiding principles for constructing an extended Hamiltonian formalism in space-like axial gauges, overcoming limitations of canonical methods and handling residual gauge fields.

Findings

Residual gauge fields regularize infrared divergences.

Propagators match Mandelstam-Leibbrandt form.

Canonical methods are insufficient for certain space-like gauges.

Abstract

Canonical methods are not sufficient to properly quantize space-like axial gauges. In this paper, we obtain guiding principles which allow the construction of an extended Hamiltonian formalism for pure space-like axial gauge fields. To do so, we clarify the general role residual gauge fields play in the space-like axial gauge Schwinger model. In all the calculations we fix the gauge using a rule, $n{\cdot}A=0$, where $n$ is a space-like constant vector and we refer to its direction as $x_-$. Then, to begin with, we construct a formulation in which the quantization surface is space-like but not parallel to the direction of $n$. The quantization surface has a parameter which allows us to rotate it, but when we do so we keep the direction of the gauge field fixed. In that formulation we can use canonical methods. We bosonize the model to simplify the investigation. We find that the antiderivative, $({\partial}_-)^{-1}$, is ill-defined whatever quantization coordinates we use as long as the direction of $n$ is space-like. We find that the physical part of the dipole ghost field includes infrared divergences. However, we also find that if we introduce residual gauge fields in such a way that the dipole ghost field satisfies the canonical commutation relations, then the residual gauge fields are determined so as to regularize the infrared divergences contained in the physical part. The propagators then take the form prescribed by Mandelstam and Leibbrandt. We make use of these properties to develop guiding principles which allow us to construct consistent operator solutions in the pure space-like case where the quantization surface is parallel to the direction of $n$ and canonical methods do not suffice.