Classical Dirac particle II. Interaction with an electromagnetic plane wave

TL;DR

This paper investigates how a classical Dirac particle interacts with an electromagnetic plane wave, showing that the wave transfers energy, momentum, and modifies the particle's spin, regardless of its charge.

Contribution

It provides a numerical analysis of the classical Dirac particle's interaction with an electromagnetic plane wave, including effects on momentum and spin.

Findings

The wave transfers energy, momentum, and angular momentum to the particle.

The particle's center of mass velocity aligns with the wave propagation.

The spin of the particle is affected by the external electromagnetic torque.

Abstract

In a previous work we have described the classical structure and analyzed the interaction of the classical Dirac particle with uniform and oscillating electric and magnetic fields. In the present paper we consider the interaction of the Dirac particle at rest with an electromagnetic plane wave packet. The integration of the dynamical equations is done numerically with a Mathematica notebook that is available to the reader. Independently of the electric charge of the Dirac particle the interaction produces a linear momentum transfer such that the center of mass of the particle is moving with a component of its CM velocity in the direction of the propagation of the wave. The electromagnetic plane wave transfers energy, linear momentum and angular momentum to the particle. The CM spin is also modified and its change depends on the torque of the external Lorentz force defined at the center of charge position with respect to the center of mass and on the work of the external force along the center of mass trajectory of the particle. We analyze how the different physical parameters of the wave and the spin orientation determine the outcome of the numerical experiment.