Operator Preparation and Characteristic Analysis of Open Quantum Systems   Based on the Lyapunov Control Method
  The control laws based on quantum Lyapunov control method are designed to prepare operators for two level open quantum systems in this paper. A novel Lyapunov function is proposed according to a matrix logarithm function. The higher accuracy and faster convergence of the novel Lyapunov function proposed are analyzed by comparing with the operator distance . We adopt three control fields, and design two types of control law forms. The first form is to use one control law to offset the influence of the dissipation, while the other one is to use all three control laws to offset the dissipation. Moreover, the robustness of the system Hamiltonian with uncertainty is further investigated to comprehend the performances of control laws. NOT gates are prepared by the designed control laws for open quantum systems as well as closed quantum systems in numerical experiments to verify the superiority of, in which the performance indexes of distance and fidelity are compared and analyzed. 
Jie Wen, Shuang Cong
math-ph math.MP quant-ph