Longitudinal angular momentum in Mie scattering from a magneto-optically active sphere: QED correction to the Einstein-de Haas effect

This work investigates the angular momentum induced by electromagnetic quantum fluctuations in a dielectric Mie sphere. The magneto-optical activity creates longitudinal electric modes with broken symmetry of magnetic quantum numbers. When excited by electromagnetic quantum fluctuations, angular momentum is created by a vortex of the Poynting vector that decays as 1/r from the center of the sphere. This longitudinal angular momentum, connected to the vector potential A(r, t), emerges as a QED modification of the traditional diamagnetic Einstein-de Haas effect, in which an applied external magnetic field, via its action on microscopic magnetism, enforces macroscopic rotation.