Magnetic Moment of Photon

Abstract

We have calculated the intrinsic magnetic moment of a photon through the intrinsic magnetic moment of a gamma photon created as a result of the electron-positron annihilation with the angular frequency ω. We show that a photon propagating in z direction with an angular frequency ω carries a magnetic moment of μ z = ±( ec /ω) along the propagation direction. Here, the (+) and (-) signs stand for the right hand and left circular helicity respectively. Because of these two symmetric values of the magnetic moment, we expect a splitting of the photon beam into two symmetric subbeams in a Stern-Gerlach experiment. The splitting is expected to be more prominent for low energy photons. We believe that the present result will be helpful for understanding the recent attempts on the Stern-Gerlach experiment with slow light and the behavior of the dark polaritons and also the atomic spinor polaritons.