Electron dynamics in quantum qubits coupled with the single electron transistor

The system of one and two qubits coupled electrostatically with the quantum dot placed between the two electron reservoirs (single electron transistor, SET) has been studied. The qubit charge oscillations and the current flowing through the SET were calculated using the equation of motion method for appropriate correlation functions. The calculations were done for constant and harmonically oscillating qubit energy levels. We also show that the SET current flowing in response to the pulse of the tunneling amplitude between the qubit quantum dots versus the pulse duration exhibits the damped oscillatory time-dependence similar to the qubit charge oscillations.