Eur. Phys. J. D (2016) 70: 263
https://doi.org/10.1140/epjd/e2016-60575-1

Regular Article

Role of the electromagnetic momentum in the spin-orbit interaction

Centro de Física Fundamental, Facultad de Ciencias, Universidad de Los Andes, 5101 Mérida, Venezuela

^a e-mail: spavieri@ula.ve

Received: 13 October 2015
Received in final form: 25 October 2016
Published online: 15 December 2016

Abstract

The role played by the linear and angular momentum of the electromagnetic fields in the understanding of several aspects of quantum mechanics is discussed. A non-relativistic semi-classical model of the spin-orbit interaction, where the electromagnetic interaction energy U is calculated in the frame of the nucleus, is presented. Taking into account the electron hidden momentum P_h = c^-1μ × E, the spin-orbit energy splitting turns out to be Δℰ_so = (1 / 2)U, the factor 1 / 2 emerging directly by requiring that the energy variation be a minimum. After quantization, the radius of the orbit is found to be spin-dependent, anticipating a feature of the Dirac equation. Finally, a test of the hidden momentum P_h, which may corroborate the approaches based on the hidden momentum and related interpretations of electrodynamics, is proposed and shown to be viable with present technology.