Has the Photon an Anomalous Magnetic Moment?

TL;DR

This paper investigates the photon’s anomalous magnetic moment induced by virtual electron-positron interactions, revealing paramagnetic behavior and a maximum near pair creation thresholds, with potential astrophysical implications.

Contribution

It presents a theoretical analysis showing the photon can have a nonzero anomalous magnetic moment influenced by external magnetic fields and energy levels, a novel insight.

Findings

Photon exhibits a nonzero anomalous magnetic moment with transverse momentum.

Anomalous magnetic moment is paramagnetic at low and high frequencies.

Maximum magnetic moment occurs near pair creation threshold, exceeding twice the electron's anomalous magnetic moment.

Abstract

Due to its interaction with the virtual electron-positron field in vacuum, the photon exhibits a nonzero anomalous magnetic moment whenever it has a nonzero transverse momentum component to an external constant magnetic field. At low and high frequencies this anomalous magnetic moment behaves as paramagnetic, and at energies near the first threshold of pair creation it has a maximum value greater than twice the electron anomalous magnetic moment. These results might be interesting in an astrophysical and cosmological context.