Is the photon paramagnetic?

Abstract

A photon exhibits a tiny anomalous magnetic moment ${\mu }_{\gamma }$ due to its interaction with an external constant magnetic field in vacuum through the virtual electron-positron background. It is paramagnetic (${\mu }_{\gamma }>0$) in the whole region of transparency, i.e. below the first threshold energy for pair creation and has a maximum near this threshold. The photon magnetic moment is different for eigenmodes polarized along and perpendicular to the magnetic field. Explicit expressions are given for ${\mu }_{\gamma }$ for the cases of photon energies smaller and closer to the first pair creation threshold. The region beyond the first threshold is briefly discussed.

References in corpus (4)

• Polarization operator approach to electron-positron pair production in combined laser and Coulomb fields
• Muon pair creation by two x-ray laser photons in the field of an atomic nucleus
• Vacuum Decay Time in Strong External Fields
• Negative Pressures in QED Vacuum in an External Magnetic Field

Cited by in corpus (4)

• Real and virtual photons in an external constant electromagnetic field of most general form
• QED with external field: Hamiltonian treatment for anisotropic medium formed by the Lorentz-non-invariant vacuum
• Few-Photon Electron-Positron Pair Creation by Relativistic Muon Impact on Intense Laser Beams
• The role of photon polarization modes in the magnetization and instability of the vacuum in a supercritical field