Anomaly in the electron orbital gyromagnetic factor: QED and radiative interactions

Abstract

Using standard Quantum Electrodynamics (QED), we have calculated the anomaly in the electron orbital g-factor, which is in reasonable agreement with experimental data. For second-order corrections, the anomaly in the orbital g-factor is of the order α/3π, while for approximations to the same order, the well-known anomaly in the electron spin g-factor where α = 1/137 is the structure constant. Unlike the spin-g anomaly, the orbital-g anomaly is not intrinsic, but depends on the atomic state, and on Z, the atomic mass. Thus, the orbital anomaly is actually (α/3π)D, where D includes the effect of the magnetic field and/or the atomic properties. Hence, we have shown that radiative interactions, which are the sources of the spin-g anomaly, also produce an orbital anomaly. It is physically reasonable to expect that radiative interactions that modify many physical properties of electrons in electromagnetic fields will also modify the orbital magnetic moment of the electron.