Spin polarization
= Spin polarization
{title2=$\mathbf P_s=2\langle\mathbf S\rangle/\hbar$}
{wiki}
For a spin-one-half ensemble, <spin polarization> measures unequal occupation or coherent alignment of <spin> states. A spin-dependent energy splitting does not alone determine the ensemble's response: occupation, <temperature> and <spin relaxation> matter. A <spin polarization> is distinct from a net change of <charge density> and from the optical <polarization of waves>.