Magnetic resonance

This animation illustrates magnetic resonance, namely the evolution of a spin in a strong magnetic field B0 submitted additionally to a rotating magnetic field B1, perpendicular to B0. When the frequency w of the rotating field is exactly equal to Larmor frequency, magnetic resonance is achieved. The spin then goes slowly but surely from state |-> to state |+>, and vice-versa. In contrast, if the frequency of the rotating field is not tuned to Larmor frequency, < Sz > oscillates only a tiny little bit aroung its average value (try for example w/w0=3.5).
Note that the field magnitudes are expressed in frequency units according to the relations hbar w0 = g B0 and hbar w1 = g B1, where g is the gyromagnetic ratio.

Note that this version is obsolete. Please see the new version.