Can active-sterile neutrino oscillations lead to chaotic behavior of the cosmological lepton asymmetry?

Understand

While the cosmic baryon asymmetry has been measured at high accuracy to be 6.1*10^-10, a corresponding lepton asymmetry could be as large as 10^-2 if it hides in the neutrino sector.

• It has been known for some time that a large asymmetry can be generated from a small initial asymmetry given the existence of a sterile neutrino with a mass less than the mass of the active neutrino.
• While the magnitude of the final lepton asymmetry is deterministic, its sign has been conjectured to be chaotic in nature.
• This has been proven in the single momentum approximation, also known as the quantum rate equations, but has up to now not been established using the full momentum dependent quantum kinetic equations.