Quantization of magnetoelectric fields

TL;DR

This paper explores the quantization of magnetoelectric fields generated by magnetic dipolar mode oscillations in ferrite disks, revealing their unique topological properties and potential to induce Casimir torques.

Contribution

It introduces a phenomenological approach to quantize ME fields in ferrite disks, highlighting their topological and quantum fluctuation characteristics, distinct from traditional electromagnetic fields.

Findings

ME fields carry spin and orbital angular momentum.

Vacuum fluctuations can induce Casimir torque.

ME fields differ from free space EM fields due to topology.

Abstract

The effect of quantum coherence involving macroscopic degree of freedom, and occurring in systems far larger than individual atoms are one of the topical fields in modern physics. Because of material dispersion, a phenomenological approach to macroscopic quantum electrodynamics, where no canonical formulation is attempted, is used. The problem becomes more complicated when geometrical forms of a material structure have to be taken into consideration. Magnetic dipolar mode (MDM) oscillations in a magnetically saturated quasi 2D ferrite disk are macroscopically quantized states. In this ferrimagnetic structure, long range dipole dipole correlation in positions of electron spins can be treated in terms of collective excitations of a system as a whole. The near fields in the proximity of a MDM ferrite disk have space and time symmetry breakings. Such MDM-originated fields, called magnetoelectric (ME) fields,carry both spin and orbital angular momentums. By virtue of unique topology, ME fields are different from free space electromagnetic (EM) fields. The ME fields are quantum fluctuations in vacuum. We call these quantized states ME photons. There are not virtual EM photons. We show that energy, spin and orbital angular momenta of MDM oscillations constitute the key physical quantities that characterize the ME field configurations. We show that vacuum can induce a Casimir torque between a MDM ferrite disk, metal walls, and dielectric samples.