Collective neutrino oscillationsin various external fields.

Abstract

Oscillation of astrophysical and cosmological neutrinos is an integral part of the evolution of supernova and the early universe. The dense background matter and strong magnetic fields, which are present in these astrophysical and cosmological media, are known to significantly influence neutrino oscillations. Recently it was discovered that neutrino self interaction, which appears in high density neutrino gas, can result in collective effects in neutrino oscillations. This phenomenon was also shown to drastically change the picture of neutrino oscillations. The main goals of this research project are: (i) to study neutrino collective oscillations on the basis of quantum kinetic approach and within the method of exact solutions of wave equations, (ii) to analyze the neutrino evolution equation, accounting for the self interaction term, using the methods of nonlinear plasma physics, and (iii) to apply the general theory of neutrino collective oscillations to the description of neutrino evolution in various realistic situations, like supernova and the early universe. (AU)