Application Of Quantum Dot System: Optically-Controlled Quantum Switch And Photon-Electron Pumping Effect

We design a four-quantum-dot system subjected to a time-dependent external field. The average current through the quantum dot system is obtained by using the method of non-equilibrium Green's function. By adjusting either the amplitude or frequency of the time-dependent external field, the average current can be converted between zero and non-zero. Based on this property, the system can be designed as an optically-controlled quantum switch device. When the asymmetric time-dependent external field is irradiated to the left and right electrodes, negative current can be observed in the current spectrum, i.e., the photon-electron pumping effect. The present work sheds lights onto design and quantum computation of future nano-devices.