研究了n比特随机量子系统实时状态估计及其反馈控制的问题.对于连续弱测量(Continuous weak measurement, CWM)过程存在高斯噪声的情况,基于在线交替方向乘子法(Online alternating direction multiplier method,OADM)推导出一种适用于...研究了n比特随机量子系统实时状态估计及其反馈控制的问题.对于连续弱测量(Continuous weak measurement, CWM)过程存在高斯噪声的情况,基于在线交替方向乘子法(Online alternating direction multiplier method,OADM)推导出一种适用于n比特随机量子系统的实时量子状态估计算法,即QSE-OADM (Quantum state estimation based on OADM).运用李雅普诺夫方法设计控制律,实现基于实时量子状态估计的反馈控制,并证明所提控制律的收敛性.以2比特随机量子系统为例进行数值仿真实验,通过与基于QST-OADM (Quantum state tomography based on OADM)算法和OPG-ADMM (Online proximal gradient-based alternating direction method of multipliers)算法的量子反馈控制方案的性能对比,验证了所提控制方案的优越性.展开更多
The compressively strained InGaAs/InGaAsP quantum well distributed feedback laser with ridge-wave- guide is fabricated at 1.74μm. It is grown by low-pressure metal organic chemical vapor deposition（MOCVD）. A strain...The compressively strained InGaAs/InGaAsP quantum well distributed feedback laser with ridge-wave- guide is fabricated at 1.74μm. It is grown by low-pressure metal organic chemical vapor deposition（MOCVD）. A strain buffer layer is used to avoid indium segregation. The threshold current of the device uncoated with length of 300μm is 11.5mA. The maximum output power is 14mW at 100mA. A side mode suppression ratio of 35.5dB is obtained.展开更多
Monolithic electro absorption modulated distributed feedback(DFB) lasers are proposed and fabricated by using a modified double stack active layer.The 38mA threshold,9dB extinction ratio (from 0 5V to 3 0V),and ab...Monolithic electro absorption modulated distributed feedback(DFB) lasers are proposed and fabricated by using a modified double stack active layer.The 38mA threshold,9dB extinction ratio (from 0 5V to 3 0V),and about 5mW output power at the 100mA operation current are achieved.Compared with other reported results (only 1 5mW at the same operation current) of the traditional stack active structure,the proposed structure improves the output power of devices.展开更多
We consider the system consisting of two qubits collectively damped, with the output being unit-efficiency measured and subsequently fed back to control the system state. Our primary goal in this paper is （i） to sol...We consider the system consisting of two qubits collectively damped, with the output being unit-efficiency measured and subsequently fed back to control the system state. Our primary goal in this paper is （i） to solve the feedback-modified master equation, （ii） to demonstrate the ability of feedback control based on the solutions, and （iii） to pick out different steady states by choosing different driving strengths and feedback strengths to counteract the effects of both damping and the measurement back-action on the system. We further investigate some properties of the equilibrium steady state, its distribution probability and entanglement vs. the driving and feedback amplitudes. We find that in our feedback model feedback plays a negative role in producing entanglement.展开更多
文摘研究了n比特随机量子系统实时状态估计及其反馈控制的问题.对于连续弱测量(Continuous weak measurement, CWM)过程存在高斯噪声的情况,基于在线交替方向乘子法(Online alternating direction multiplier method,OADM)推导出一种适用于n比特随机量子系统的实时量子状态估计算法,即QSE-OADM (Quantum state estimation based on OADM).运用李雅普诺夫方法设计控制律,实现基于实时量子状态估计的反馈控制,并证明所提控制律的收敛性.以2比特随机量子系统为例进行数值仿真实验,通过与基于QST-OADM (Quantum state tomography based on OADM)算法和OPG-ADMM (Online proximal gradient-based alternating direction method of multipliers)算法的量子反馈控制方案的性能对比,验证了所提控制方案的优越性.
基金Supported by National Natural Science Foundation of China(61205067,61307088)the Fundamental Research Funds for the Central Universities(ZYGX2013J007,ZYGX2012J008)
文摘The compressively strained InGaAs/InGaAsP quantum well distributed feedback laser with ridge-wave- guide is fabricated at 1.74μm. It is grown by low-pressure metal organic chemical vapor deposition（MOCVD）. A strain buffer layer is used to avoid indium segregation. The threshold current of the device uncoated with length of 300μm is 11.5mA. The maximum output power is 14mW at 100mA. A side mode suppression ratio of 35.5dB is obtained.
文摘Monolithic electro absorption modulated distributed feedback(DFB) lasers are proposed and fabricated by using a modified double stack active layer.The 38mA threshold,9dB extinction ratio (from 0 5V to 3 0V),and about 5mW output power at the 100mA operation current are achieved.Compared with other reported results (only 1 5mW at the same operation current) of the traditional stack active structure,the proposed structure improves the output power of devices.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10775100,10974137 and 10805034the Fund of Theoretical Nuclear Center of HIRFL of Chinathe Scientific Research Foundation of CUIT under Grant No.KYTZ201024
文摘We consider the system consisting of two qubits collectively damped, with the output being unit-efficiency measured and subsequently fed back to control the system state. Our primary goal in this paper is （i） to solve the feedback-modified master equation, （ii） to demonstrate the ability of feedback control based on the solutions, and （iii） to pick out different steady states by choosing different driving strengths and feedback strengths to counteract the effects of both damping and the measurement back-action on the system. We further investigate some properties of the equilibrium steady state, its distribution probability and entanglement vs. the driving and feedback amplitudes. We find that in our feedback model feedback plays a negative role in producing entanglement.
