i.e., a combination of $\pi$ and $\sigma$ ($\sigma$ refers to light that has a linear polarization orthogonal to the QA and that thus induces $\sigma^+$ and $\sigma^-$ transitions). The dark state is now the superposition state $$|\text{DS}_{1,2}\rangle = \frac{1}{\sqrt{2}} (|1\rangle - i|2\rangle),$$ for which $\langle 7 |V_\mathrm{c}|\text{DS}_{1,2}\rangle = \langle 8 |V_\mathrm{c}|\text{DS}_{1,2}\rangle = 0$. If we apply a magnetic field in the direction of the QA ($\mathbf{u}_x$), $|\text{DS}_{1,2}\rangle$ is no longer an energy eigenstate, but the dark state evolves in time $$\label{eq:DStimedep}
|\text{DS}_{1,2}\rangle (t) = \frac{e^{-i\omega_gt}}{\sqrt{2}}
(e^{ig_g\mu_\mathrm{B}Bt/2\hbar}|1\rangle - i e^{-ig_g\mu_\mathrm{B}Bt/2\hbar}|2\rangle).$$ When the field is strong enough that the evolution rate of the dark state $g_g \mu_\mathrm{B} B/\hbar$ is higher than the optical pumping rate $\Gamma_\mathrm{op}$ (corresponding to $B\approx 35\;\mu$T for the parameters in Fig. \[fig:g-states\]), the system cannot follow and the dark state is destabilized. Another way to explain this is that the optical pumping rate $\Gamma_\mathrm{op}$ determines the width of the ground states, and the Zeeman shift of the ground levels tune the $\Lambda$ system out of Raman (CPT) resonance. When $g_g \mu_\mathrm{B} B/\hbar \approx 10 \Gamma_\mathrm{op}$ ($B\approx 350\;\mu$T), the dark state is completely destabilized; see the dashed (red) curve in Fig. \[fig:g-states\]. If the field is increased further so 