Nonlinear flavor-wave turbulence

Establish whether a quantitative theory of nonlinear flavor-wave turbulence can be developed, and determine the quantities, cascades, spectra, and stationary states associated with such turbulence.

Background

The paper distinguishes nonlinear wave–wave interactions from quasi-linear neutrino–wave relaxation. Such interactions may transfer excitation between scales and generate coherent or turbulent structures, but their systematic theoretical treatment remains unresolved.

References

What is the role of nonlinear wave--wave interactions? Quasi-linear evolution retains the exchange of flavor between neutrinos and waves. Nonlinear flavor-wave interactions may transfer excitation between scales, generate coherent structures, or produce a turbulent spectrum before wave--particle relaxation has removed the instability. It remains to be understood whether a quantitative theory of flavor-wave turbulence can be developed, what quantities such turbulence transports, and whether it exhibits cascades, universal spectra, or statistically stationary states.

— Collective flavor conversion in dense neutrino plasmas  (2609.19256 - Fiorillo, 16 Sep 2026) in Section 8, Outlook