The former is a famous quantum mechanical effect known as Larmor precession
, while the latter was considered previously by Rabi in .
One has to take into consideration that magnetic moment acts like a top, and, in non-relativistic case, precession of the nucleus is simple Larmor precession
. Relativistic case was described by Bargman et al .
The angular velocity of the magnetization in this Larmor precession
is [omega]L = [gamma]M x B/[M.sub.[perpendicular]], where [M.sub.[perpendicular]] is the projection of M on the plane perpendicular to B.
(usually small) additional Larmor precession
angle in the xy plane due
frequency must match the Larmor precession
frequency in the static field coils, reaching the maximum frequency of operation of the r.f.
To reach this goal, the adiabatic condition has to be fullfilled: changes [dot.B] of the magnetic field (especially rotations of the field vector) seen by the moving neutron normalized to the absolute value of the magnetic flux density B have to be much slower than the neutron Larmor precession
in the magnetic field [[omega].sub.L]
In the polarized nuclear target, Larmor precession
must be cancelled by pseudomagnetic precession  to keep the T-odd correlation [s.sub.n] * ([k.sub.n] X I).
By this term we mean a magnetometer whose sensitive elements sense the field in the same region where the UCN are undergoing Larmor precession
. If there is one essential point that has been learned during the past 25 years of experimental work in this field, it is the fact that a co-magnetometer is essential if one is to reach sensitivities comparable to or better than those currently achieved.
The pumping process produces a polarization (magnetization) in the sample which undergoes a Larmor precession
with the frequency [[omega].sub.L].
Unfortunately, the (PC) Larmor precession
of a typical cold neutron (5 [Angstrom]) due to the Earth's magnetic field is approximately 10 rad/m, while [[phi].sub.PV](n,[alpha]) as calculated using the DDH "best values" is only (-0.1[+ or -]1.15) X [10.sup.-6] rad/m.