Physical Degrees of Freedom for Gauge Fields and the Issue of Spin

TL;DR

This paper discusses the mismatch between the physical degrees of freedom of gauge bosons and their description via Lorentz group representations, addressing implications for linear and angular momentum in gauge theories.

Contribution

It clarifies the relationship between gauge field degrees of freedom and Lorentz group irreps, highlighting issues in describing gauge bosons' spin and momentum.

Findings

Identifies conflicts between gauge degrees of freedom and Lorentz representations.

Analyzes implications for linear and angular momentum of gauge fields.

Provides insights into the proper description of gauge boson spin.

Abstract

The conflict between the physical degrees of freedom of gauge bosons and the Lorentz group irreps naturally used to describe their couplings to matter fields are illustrated and discussed, and applied to issues of linear and angular momentum.