We theoretically investigate single-photon polarization conversion via scattering by an atom with Λ configuration coupled to a semi-infinite waveguide and discuss the two cases in which the Λ system is non-degenerat...We theoretically investigate single-photon polarization conversion via scattering by an atom with Λ configuration coupled to a semi-infinite waveguide and discuss the two cases in which the Λ system is non-degenerated and degenerated. By applying the hard-wall boundary condition of the semi-infinite waveguide, it is found that singlephoton polarization conversion can be realized with unit probability for both cases under the ideal condition.Together with the polarization conversion, the frequency conversion of a single photon can also be realized with unit probability in the ideal case if the Λ system is not degenerated.展开更多
A new control algorithm is presented for digitally controlled dc-dc converters to achieve a fast response under a successive load-change.Under the steady-state condition,the tight voltage regulation is processed by th...A new control algorithm is presented for digitally controlled dc-dc converters to achieve a fast response under a successive load-change.Under the steady-state condition,the tight voltage regulation is processed by the conventional digital PID compensator.If the load disturbance is significant,the controller switches to an optimal control scheme.With the integration of the capacitor current,the proposed algorithm predicts the optimal switch over time based on the charge balance control,and the minimal voltage derivation and recovery time are thus achieved when the load current has a successive load-change.The method for calculating the optimal switch over time is described,and the implementation of the proposed algorithm with a digital controller is treated in detail.Furthermore,the simulation and experiment results are provided to validate the effectiveness of the approaches.展开更多
基金Supported by the Anhui Provincial Natural Science Foundation under Grant Nos 1608085MA05 and 1608085MA09the National Natural Science Foundation of China under Grant Nos 11774262 and 11474003
文摘We theoretically investigate single-photon polarization conversion via scattering by an atom with Λ configuration coupled to a semi-infinite waveguide and discuss the two cases in which the Λ system is non-degenerated and degenerated. By applying the hard-wall boundary condition of the semi-infinite waveguide, it is found that singlephoton polarization conversion can be realized with unit probability for both cases under the ideal condition.Together with the polarization conversion, the frequency conversion of a single photon can also be realized with unit probability in the ideal case if the Λ system is not degenerated.
基金Supported by the National Natural Science Foundation of China(51207001)the Anhui Provincial Natural Science Foundation(1308085ME66)
文摘A new control algorithm is presented for digitally controlled dc-dc converters to achieve a fast response under a successive load-change.Under the steady-state condition,the tight voltage regulation is processed by the conventional digital PID compensator.If the load disturbance is significant,the controller switches to an optimal control scheme.With the integration of the capacitor current,the proposed algorithm predicts the optimal switch over time based on the charge balance control,and the minimal voltage derivation and recovery time are thus achieved when the load current has a successive load-change.The method for calculating the optimal switch over time is described,and the implementation of the proposed algorithm with a digital controller is treated in detail.Furthermore,the simulation and experiment results are provided to validate the effectiveness of the approaches.
