Generalized Dirac-Pauli equation and spin light of neutrino in magnetized matter

We consider propagation of a massive neutrino in matter within the quantum approach based on the two equations for the neutrino field: the first one is the Dirac-Pauli equation for a massive neutrino in an external magnetic field generalized on the inclusion of effects of the background matter; the second one is the modified Dirac equation derived directly from the neutrino-matter interaction Lagrangian. On the basis of these two equations the quantum theory of a neutrino moving in the background matter is developed (the exact solutions of these equations are found and classified over the neutrino spin states, the corresponding energy spectra are also derived). Using these solutions we study within the quantum approach the spin light of neutrino ($SL\nu$) in matter with the effect of a longitudinal magnetic field being also incorporated. In particular, the $SL\nu$ radiation rate and total power are derived. The use of the generalized Dirac-Pauli equation also enables us to consider the $SL\nu$ in matter polarized under the influence of strong magnetic field.