# Always remember & never forget . . .

... the Fermi Golden Rule:

$$B(\omega,v-v_*)=\frac{1}{8\pi^2}|\omega\cdot(v-v_*)||{\widehat \phi} ((\omega\cdot(v-v_*))\omega)|^2$$

---you know, where the hat $\sphat$ denotes the Fourier transform and $\phi$ is a two-body interaction potential.
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