N-mode coherence in collective neutrino oscillations. (arXiv:1103.2891v4 [hep-ph] UPDATED)
<a href="http://arxiv.org/find/hep-ph/1/au:+Raffelt_G/0/1/0/all/0/1">Georg G. Raffelt</a>

We study two-flavor neutrino oscillations in a homogeneous and isotropic
ensemble under the influence of neutrino-neutrino interactions. For any density
there exist forms of collective oscillations that show self-maintained
coherence. They can be classified by a number N of linearly independent
functions that describe all neutrino modes as linear superpositions. What is
more, the dynamics is equivalent to another ensemble with the same effective
density, consisting of N modes with discrete energies E_i with i=1, …, N. We
use this equivalence to derive the analytic solution for two-mode (bimodal)
coherence, relevant for spectral-split formation in supernova neutrinos.

We study two-flavor neutrino oscillations in a homogeneous and isotropic
ensemble under the influence of neutrino-neutrino interactions. For any density
there exist forms of collective oscillations that show self-maintained
coherence. They can be classified by a number N of linearly independent
functions that describe all neutrino modes as linear superpositions. What is
more, the dynamics is equivalent to another ensemble with the same effective
density, consisting of N modes with discrete energies E_i with i=1, …, N. We
use this equivalence to derive the analytic solution for two-mode (bimodal)
coherence, relevant for spectral-split formation in supernova neutrinos.

http://arxiv.org/icons/sfx.gif