Quantum field rephasing
= Quantum field rephasing
{title2=$\psi_i\mapsto e^{i\alpha_i}\psi_i$}
Multiplying individual fields by constant phases changes the apparent phases of interaction coefficients. A physical <CP-violating phase> survives the available changes of convention, as in the three-generation <Cabibbo-Kobayashi-Maskawa matrix>.