Spindensities in Pseudo-classical kinetic theory

TL;DR

This paper investigates the classical limit of relativistic transport theories for spin 1/2 fermions, showing that spindensities vanish while dipole-densities may persist, through a comparison with supersymmetric classical mechanics.

Contribution

It provides a detailed analysis of the classical limit of relativistic spin transport, highlighting the behavior of spindensities and dipole-densities in this regime.

Findings

Spindensities vanish in the classical limit.

Dipole-densities may survive in the classical limit.

Comparison with N=1 supersymmetric classical mechanics clarifies spin contributions.

Abstract

In this paper the classical limit of relativistic transport theories for spin 1/2 fermions is examined through a comparison with the classical kinetic theory derived from N=1 supersymmetric classical mechanics. The conclusion is that in the classical limit spindensities, i.e. the axial-vector contribution to the relativistic Wigner-function, vanishes and dipole-densities, i.e. the spin-tensor contributions to the relativistic Wigner function, may survive.