Compton Effect in the Medium with Non-unity Refractive Index

The foundations of the modern quantum theory of electro-magnetic radiation and its interaction with medium are constituted by the Einstein's theory of photo-effect and the theory of Compton effect. However, in the theory proposed by Compton and subsequent refinements, the medium features in explicit form are not generally accounted at all. This theory is based on the relationship between the photon momentum and its energy that may take place only in vacuum, but not in a medium with non-unity refractive index n. Here, we use Abraham's representation for the momentum of a photon in medium for the creation of a new consistent Compton effect theory accounting for media features. A new condition under which anomalous Compton effect is possible, is defined. In our case, due to the photon scattering on a moving electron, the photon's energy can increase when the electron velocity is above a threshold value, in analogy with the Vavilov-Cherenkov radiation effect. In our theory we also provide a new description of the parameters for scattered electrons, which is important for the experimental determination of the dependence of the Compton effect in medium on refractive index n.