Photon Magnetic Moment and Vacuum Magnetization in an Asymptotically Large Magnetic Field

TL;DR

This paper investigates how strong magnetic fields affect vacuum energy and introduces the concept of a photon anomalous magnetic moment, revealing the vacuum's magnetization response and its implications for quantum electrodynamics.

Contribution

It analyzes the photon anomalous magnetic moment in superstrong magnetic fields and links it to vacuum magnetization, extending the understanding of electromagnetic radiation as a source of vacuum magnetization.

Findings

Photon magnetic moment has two orthogonal components in a strong magnetic field.

Vacuum exhibits a paramagnetic response in one polarization mode.

The vacuum magnetization density is slightly modified by photon corrections.

Abstract

We consider the effect of the photon radiative correction on the vacuum energy in a superstrong magnetic field. The notion of a photon anomalous magnetic moment is analyzed and its connection with the quasiparticle character of the electromagnetic radiation is established. In the infrared domain the magnetic moment turns out to be a vector with two orthogonal components in correspondence with the cylindrical symmetry imposed by the external field. The possibility of defining such quantity in the high energy limit is studied as well. Its existence suggests that the electromagnetic radiation is a source of magnetization to the whole vacuum and thus its electron-positron zero-point energy is slightly modified. The corresponding contribution to the vacuum magnetization density is determined by considering the individual contribution of each vacuum polarization eigenmode in the Euler-Heisenberg Lagrangian. A paramagnetic response is found in one of them, whereas the remaining ones are diamagnetic. Additional issues concerning the transverse pressures are analyzed.