Natural linewidth
= Natural linewidth
{title2=$\Gamma$}
For a closed <two-level system> with <spontaneous emission> population decay $P_e(t)=P_e(0)e^{-\Gamma t}$ and no additional <dephasing>, the <natural linewidth> has <full width at half maximum> $\Gamma$ in <angular frequency>, or $\Gamma/(2\pi)$ in <hertz>. The excited-state lifetime is $1/\Gamma$.