Transverse relaxation
= Transverse relaxation
{title2=$T_2^{-1}=\Gamma=T_1^{-1}/2+\gamma_\phi$}
Decay of the off-diagonal coherence of a two-level <density operator>. Population relaxation contributes half its total rate; additional <dephasing> contributes $\gamma_\phi\geq0$ in the usual completely positive two-level model. Thus transverse relaxation should not automatically be identified with pure dephasing alone.