Magnetic dipole transition
= Magnetic dipole transition
A transition driven by an oscillating <magnetic field> through $H'=-\boldsymbol\mu\cdot\mathbf B$. The rank-one magnetic operator preserves parity and allows changes in total <angular momentum> of zero or one, excluding zero-to-zero. Its spherical components select changes in the <angular momentum> component of $0,\pm1$. Hyperfine clock states can therefore couple even when each has zero first-order static magnetic moment.