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
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Note that this version is obsolete.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.