Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The dispersion relation of the fast neutrino oscillation wave   A dense neutrino medium can support flavor oscillation waves which are
coherent among different momentum modes of the neutrinos. The dispersion
relation (DR) branches of such a wave with complex frequencies and/or wave
numbers can lead to the exponential growth of the wave amplitude which in turn
will engender a collective flavor transformation in the neutrino medium. In
this work we propose that the complex DR branches of the neutrino oscillation
wave should be bound by the critical points of the DR. We demonstrate how this
theory can be applied to the neutrino medium with an (approximate) axial
symmetry about the propagation direction of the neutrino oscillation wave. We
also show how the flavor instabilities in this medium can be identified by
tracing the critical points of the DR as the electron lepton number
distribution of the neutrino medium is changed continuously.

18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph