Rate-equation approach for a charge qudit

We theoretically describe the two-electron four-level double quantum dot (DQD) tunnel-coupled to a fermionic sea by using the rate-equation formalism. This approach allows to find occupation probabilities of each DQD level in a relatively simple way, compared to other methods. Calculated dependencies were compared with the experimental results. The system under study is irradiated by a strong driving signal and as a result one can observe Landau-Zener-Stuckelberg-Majorana (LZSM) interferometry patterns which are successfully described by the considered formalism. The system operation regime depends on the amplitude of the excitation signal and the energy detuning, so one can transfer the system to the necessary quantum state in the most efficient way by setting these parameters. Obtained results give useful insights about initializing, characterizing and controlling the system quantum states.