Geometrical derivation of Wigner's angle for arbitrary Lorentz transformations of massless particles
Quantum Physics
2026-05-19 v1
Abstract
This note summarizes the physics and mathematics of Lorentz transformations for massless particles, specifically for photons. We provide a complete analytical derivation of Wigner's little group matrix and a closed formula for the calculation of Wigner's angle for arbitrary Lorentz transformations. Our derivation highlights the geometrical content of the sequence of little group transformations leading to Wigner's matrix and links it to classical theorems in spherical trigonometry.
Keywords
Cite
@article{arxiv.2605.18440,
title = {Geometrical derivation of Wigner's angle for arbitrary Lorentz transformations of massless particles},
author = {Isabella Cerutti and Petra F. Scudo},
journal= {arXiv preprint arXiv:2605.18440},
year = {2026}
}