Testing common approximations of neutrino fast flavor conversion

Understand

A new chapter is opening in the theory of core-collapse supernovae and neutron star mergers as simulations of these events begin to incorporate fast flavor conversion (FFC) and other forms of neutrino flavor mixing.

• Using numerical experiments, we show that the approximations of FFC that have been implemented so far are limited by at least two of three factors: (1) approximating continuous evolution as a discrete sequence of instabilities, (2) using spatially homogeneous asymptotic states, and (3) assuming that FFC must be accompanied by instability.
• The factors we identify in this work will be important considerations as the research area progresses from initial exploratory studies to more quantitatively precise assessments.