Population Transfer Manipulated by Composite Pulse Sequences in the Ladder-Type Multi-State Quantum System

A method is proposed to achieve quantum state manipulation and population transfer in the ladder-type quantum system using composite pulse sequences. First, using the Morris-Shore transformation, the two-level propagation operator is used to describe the evolution of the multi-state quantum system. Then by increasing the number of pulse sequences with well-defined relative phase, quantum state manipulation and population transfer with high efficiency and high robustness are realized while the unwanted transition is effectively suppressed. After that, the influence of Rabi frequency ratio, the change of pulse area, and the single photon detuning on the population transfer efficiency is studied with numerical calculation. It is proved that the complex pulse manipulation method used in two-level quantum systems can also be applied to multi-state quantum systems and the parameter perturbations can be compensated automatically. This technology of composite pulse sequences can be used to overcome the efficiency reduction in the quantum manipulation process caused by polarization impurity, laser frequency deviation and parameter disturbance. This method is of great significance to the quantum gate construction and quantum simulation.