and δ δ = ω ω − − ω ω 0 is the detuning and measures how far the light frequency, ω ω , is from the transition, ω ω 0 . Here, d → → g , e is the transition dipole moment for the g → → e transition and E → → 0 = ϵ ϵ ^ ^ E 0 is the vector electric field amplitude including the polarization (in the sense E → → = E 0 → → 2 e − − i ω ω t + c . c . ).