Ultrafast Manipulation of a Double Quantum-Dot Charge Qubit Using Lyapunov-Based Control Method

摘要

For a two-level double quantum-dot (DQD) system, we proposed an alternative ultrafast manipulation approach, Lyapunov-based control method, to transfer the charge qubit from the initial charge state to the target charge state on the picosecond scale. Better control performance is obtained compared with that via Landau–Zener–Stückberge–Majorana interference, and the designed control fields can be implemented in the actual experiment facility. The control process is composed of three parts: first, a slope pulse takes the system from a positive detuning adiabatically to the anticrossing point, which corresponds to the resonance state of the system; then, a Lyapunov-based control pulse drives the charge qubit transfer nonadiabatically; finally, another slope pulse takes the system away from the anticrossing point to keep the system stable. The charge qubit transfer performance and the function of Lyapunov-based control pulse were studied under different control parameters. Simulation results showed that the designed Lyapunov-based control pulse has a rise time , which is in the scope of the Tektronix AWG70000A series arbitrary waveform generator and results in a significant probability for the transition from the initial charge state to the target charge state . The fidelity of the control process designed can achieve . This is the firs- result directly applicable for a DQD charge qubit transfer using the Lyapunov-based control method.