Fast Neutrino Flavor Conversion at Late Time

Understand

We study the fully nonlinear fast flavor evolution of neutrinos in 1+1 dimensions.

• Our numerical analysis shows that at late time the system reaches an approximately steady state.
• Using the steady state approximation we analytically show that the spatial variation of the polarization vectors is given by their precession around a common axis, which itself has a motion reminiscent of a gyroscopic pendulum.
• We then show that the steady state solution to the equations of motion cannot be separated in position and velocity, that is the motion is not collective in the usual sense.