Theory of active dephasing control in qubit arrays

We develop a theory of active dephasing control of qubit systems in array structures by using the multi-wave mixing technique. Assuming an acoustic phonon with a cutoff frequency ωc as the reservoir boson, we evaluate the state evolution of the qubit–reservoir system under irradiation of an optical pulse sequence. The effect of active dephasing control by the optical π pulses would be observed as diffracted echo signals in the phase-matching direction. The analysis for the case of weak pulse control is also presented.