We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a singl...We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a single A-type three-level fluxonium qubit, the coherent population trapping could be obtainable and it is very sensitive to the relative phase and amplitudes of the applied fields. When the relative phase is tuned to 0 or π, the maximal atomic coherence is present and coherent population trapping occurs. While for the choice of π/2, the atomic coherence becomes weak. Meanwhile, for the fixed relative phase π/2, the value of coherence would decrease with the increase of Rabi frequency of the external field coupled with two lower levels. The responsible physical mechanism is quantum interference induced by the control fields, which is indicated in the dressed-state representation. The microwave coherent phenomenon is present in our scheme, which will have potential applications in optical communication and nonlinear optics in solid-state devices.展开更多
为解决双向DC-DC变换器(dual active bridge,DAB)采用单移相(single-phase-shift,SPS)控制产生的回流功率较高及动态性能较差的问题,提出一种采用双重移相(dual-phase-shift,DPS)控制下的最小回流功率算法与直接功率控制相结合的方法。...为解决双向DC-DC变换器(dual active bridge,DAB)采用单移相(single-phase-shift,SPS)控制产生的回流功率较高及动态性能较差的问题,提出一种采用双重移相(dual-phase-shift,DPS)控制下的最小回流功率算法与直接功率控制相结合的方法。首先对DPS控制下的基本原理及回流功率特性进行分析,并建立回流功率与移相比之间的数学关系,从而推导出各分段条件下回流功率在各阶段最小化的方案。其次在保证对变换器回流功率最小化的同时提出结合直接功率法来显著提高变换器的动态性能。最后通过MATLAB/Simulink中建立的仿真验证了上述控制策略的有效性。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11165008 and 11365009)the Foundation of Young Scientist of Jiangxi Province,China(Grant No.20142BCB23011)the Scientific Research Foundation of Jiangxi Provincial Department of Education(Grant No.GJJ13348)
文摘We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a single A-type three-level fluxonium qubit, the coherent population trapping could be obtainable and it is very sensitive to the relative phase and amplitudes of the applied fields. When the relative phase is tuned to 0 or π, the maximal atomic coherence is present and coherent population trapping occurs. While for the choice of π/2, the atomic coherence becomes weak. Meanwhile, for the fixed relative phase π/2, the value of coherence would decrease with the increase of Rabi frequency of the external field coupled with two lower levels. The responsible physical mechanism is quantum interference induced by the control fields, which is indicated in the dressed-state representation. The microwave coherent phenomenon is present in our scheme, which will have potential applications in optical communication and nonlinear optics in solid-state devices.
文摘为解决双向DC-DC变换器(dual active bridge,DAB)采用单移相(single-phase-shift,SPS)控制产生的回流功率较高及动态性能较差的问题,提出一种采用双重移相(dual-phase-shift,DPS)控制下的最小回流功率算法与直接功率控制相结合的方法。首先对DPS控制下的基本原理及回流功率特性进行分析,并建立回流功率与移相比之间的数学关系,从而推导出各分段条件下回流功率在各阶段最小化的方案。其次在保证对变换器回流功率最小化的同时提出结合直接功率法来显著提高变换器的动态性能。最后通过MATLAB/Simulink中建立的仿真验证了上述控制策略的有效性。
