Influence of homodyne-based feedback control on the entropic uncertainty in open quantum system  

作　　者：Juju Hu Qin Xue 胡菊菊;薛琴(College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, China;Key Laboratory of Photoelectronics and Telecommunication of Jiangxi Province, Nanchang 330022, China)

机构地区：[1]College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, China [2]Key Laboratory of Photoelectronics and Telecommunication of Jiangxi Province, Nanchang 330022, China

出　　处：《Chinese Physics B》2019年第7期137-143,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.61663016 and 11404150)

摘　　要：For an open quantum system containing two qubits under homodyne-based feedback control, we investigate the dynamical behaviors of quantum-memory-assisted entropic uncertainty.Moreover, we analyze the influence of feedback modes and coefficients on the entropic uncertainty.Numerical investigations show that the memory qubit should be placed in a non-dissipative channel if the single dissipative channel condition can be chosen, which helps reduce the entropic uncertainty of the system.For the homodyne feedback control F =λσx(or F =λσy), due to different roles of the entangled qubits A and B, when they are subject to feedback control with different feedback coefficients λ, the exchange of feedback coefficients will cause variations of the entropic uncertainty.When the feedback coefficient corresponding to the memory qubit B is larger(λB >λA), the steady value of the entropic uncertainty will be small, which is conducive to enhancing the robustness of the system.However, for the feedback control F =λσz, the difference between the feedback coefficients has no effect on the steady values of the entropic uncertainty.For an open quantum system containing two qubits under homodyne-based feedback control, we investigate the dynamical behaviors of quantum-memory-assisted entropic uncertainty.Moreover, we analyze the influence of feedback modes and coefficients on the entropic uncertainty.Numerical investigations show that the memory qubit should be placed in a non-dissipative channel if the single dissipative channel condition can be chosen, which helps reduce the entropic uncertainty of the system.For the homodyne feedback control F = λ σ_x(or F = λ σ_y), due to different roles of the entangled qubits A and B, when they are subject to feedback control with different feedback coefficients λ, the exchange of feedback coefficients will cause variations of the entropic uncertainty.When the feedback coefficient corresponding to the memory qubit B is larger(λ_B > λ_A), the steady value of the entropic uncertainty will be small, which is conducive to enhancing the robustness of the system.However, for the feedback control F = λ σ_z, the difference between the feedback coefficients has no effect on the steady values of the entropic uncertainty.

关 键 词：homodyne-based feedback control quantum-memory-assisted entropic uncertainties MEMORY qubit open QUANTUM system 

分 类 号：O4[理学—物理]