Models¶

Homogeneous and Isotropic Neutrino Gas¶

$\vec P_\omega$ can be time-independent.

Regarding the discussion in Pictures, we know immediately that $\vec H$ is aligned or anti-aligned with $\vec P_\omega$ since

$\vec H \times \vec P_\omega = 0,$

as $\vec P_\omega$ is time-independent.

Anyway the equation we need to solve is then

$\vec a$

Without solving the equation, we know that