Synchronization vs. decoherence of neutrino oscillations at intermediate densities

Abstract

We study collective oscillations of a two-flavor neutrino system with arbitrary but fixed density. In the vacuum limit, modes with different energies quickly de-phase (kinematical decoherence), whereas in the limit of infinite density they lock to each other (synchronization). For intermediate densities, we find different classes of solutions. There is always a phase transition in the sense of partial synchronization occurring only above a density threshold. For small mixing angles, partial or complete decoherence can be induced by a parametric resonance, introducing a new time scale to the problem, the final outcome depending on the spectrum and mixing angle. We derive an analytic relation that allows us to calculate the late-time degree of coherence based on the spectrum alone.

11 pages, including 13 figures. Clarifying paragraphs and 2 figures added; results unchanged. Matches published version in PRD

References in corpus (6)

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• Multiple Spectral Splits of Supernova Neutrinos
• The multi-angle instability in dense neutrino systems
• Adiabaticity and spectral splits in collective neutrino transformations
• Decoherence in supernova neutrino transformations suppressed by deleptonization
• Self-induced decoherence in dense neutrino gases