The intensity red circle represents the occupation probability of the state "up", and the intensity green circle represents the occupation probability of the state "down". The solid black lines are the instantaneous energy eigenvalues, and the red and the green dashed lines are the average, or diabatic, energies of the states "up" and "down". The blue dashed line corresponds to the bias point, including the driving signal. In the case of completely destructive interference, the mixing between the two states at each crossing exactly cancels the mixing that occurred at the previous crossing. As a result, after a full driving cycle the system goes back to its initial state (up to a relative phase).