This paper studies the real-time optimal state estimation-based feedback control for twolevel stochastic quantum systems in the non-Markovian case.The system model is established by combining the time-convolutionless ...This paper studies the real-time optimal state estimation-based feedback control for twolevel stochastic quantum systems in the non-Markovian case.The system model is established by combining the time-convolutionless non-Markovian master equation and the stochastic master equation.A nonlinear filter based on the state-dependent Riccati equation is designed in order to achieve the realtime optimal estimation of quantum states.A quadratic function multiplied with an exponential term is selected as the Lyapunov function,and a continuous-time control law is deduced via the stochastic Lyapunov stability theorem to realize eigenstate feedback control based on real-time optimal state estimation.Numerical simulation results illustrate that the proposed control scheme is capable of steering the two-level quantum system from an arbitrary initial state to the desired eigenstate with a fidelity higher than 99%within a time of 3 a.u.展开更多
One qubit subjected to the effect of phase damping in a two-level quantum system with arbitrary pure initial state is studied in this paper. The aim of this paper is to find the optimal control scheme to correct the q...One qubit subjected to the effect of phase damping in a two-level quantum system with arbitrary pure initial state is studied in this paper. The aim of this paper is to find the optimal control scheme to correct the qubit back as close as possible to its initial state. The strength-dependent measurements and control correction rotation in different bases are designed to protect the arbitrary pure state of qubit. The authors design the optimal weak measurement strength to achieve the best trade-off between gaining the information of the system and the disturbance through measurement.The authors study the suppression of phase damping in two cases: There is and isn’t the y component in initial state. The authors deduce the optimal parameters and performances of the control schemes for the various initial state situations. Simulation results demonstrate the effectiveness of the proposed control schemes.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.61973290。
文摘This paper studies the real-time optimal state estimation-based feedback control for twolevel stochastic quantum systems in the non-Markovian case.The system model is established by combining the time-convolutionless non-Markovian master equation and the stochastic master equation.A nonlinear filter based on the state-dependent Riccati equation is designed in order to achieve the realtime optimal estimation of quantum states.A quadratic function multiplied with an exponential term is selected as the Lyapunov function,and a continuous-time control law is deduced via the stochastic Lyapunov stability theorem to realize eigenstate feedback control based on real-time optimal state estimation.Numerical simulation results illustrate that the proposed control scheme is capable of steering the two-level quantum system from an arbitrary initial state to the desired eigenstate with a fidelity higher than 99%within a time of 3 a.u.
基金supported by the National Natural Science Foundation of China under Grant No.61573330the National Natural Science Foundation of International(Regional)Cooperation and Exchanges Project under Grant No.61720106009
文摘One qubit subjected to the effect of phase damping in a two-level quantum system with arbitrary pure initial state is studied in this paper. The aim of this paper is to find the optimal control scheme to correct the qubit back as close as possible to its initial state. The strength-dependent measurements and control correction rotation in different bases are designed to protect the arbitrary pure state of qubit. The authors design the optimal weak measurement strength to achieve the best trade-off between gaining the information of the system and the disturbance through measurement.The authors study the suppression of phase damping in two cases: There is and isn’t the y component in initial state. The authors deduce the optimal parameters and performances of the control schemes for the various initial state situations. Simulation results demonstrate the effectiveness of the proposed control schemes.
