# How to get from angular velocity to acquired phase for neutrino oscillations in matter?

I am reading Akhmedovs 2000 paper on parametric resonance, and I cannot figure out the math of this particular passage:

The difference of the neutrino eigenenergies in a matter of density $N_i$ is $2\omega_i$, so that the oscillations phases aquired over the intervals $T_1$ and $T_2$ are

$2\phi_1=2\omega_1T_1$, $2\phi_2=2\omega_2T_2$

My question here is: What is the relevant formula that links eigenenergy to phase? And angular velocity to eigenenergy?

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How familiar are you with the mathematics of neutrino oscillations in the first place? Do you understand how it all works in free space? –  dmckee Mar 18 '13 at 15:44
Some of the basic math of vacuum oscillation is reproduced in my answer to "How can neutrinos oscillate though the lepton flavors have differing masses?". –  dmckee Mar 18 '13 at 17:24