Probing Neutrino Quantum Kinetics in the Early Universe

We study the quantum kinetic evolution of neutrinos in the early universe where the hot and dense conditions result in neutrino interactions with matter and other neutrinos and anti-neutrinos. In these conditions, neutrino evolution is influenced by two competing effects: quantum coherence which builds up quantum phase and the kinetic destruction of this phase through inelastic scattering. Under these conditions, neutrino-neutrino interactions can cause non-linear evolution. We solve the quantum kinetic equations with full collision integrals for neutrino states in the early universe, moments after the Big Bang, and discuss the solutions.