论文标题
关于封闭的$λ$系统的光学泵送的最佳性，中间激发态的衰减率很高
On the optimality of optical pumping for a closed $Λ$-system with large decay rates of the intermediate excited state
论文作者
论文摘要
我们使用最佳控制理论来表明，对于一个封闭的$λ$系统，激发的中间水平衰减以较低的速度降低到较低的水平，较低级别之间的总体转移最佳方案实际上是光泵的。为了获得此结果，我们利用较大的衰减速率以绝热地消除了弱耦合的激发态，然后对由黑暗和明亮状态组成的基础进行转换，最后对该转换的系统应用最佳控制。随后，我们使用数值最佳控制确认了原始封闭$λ$系统的光学泵送方案的最佳性。我们还以数值证明，当对目标状态的衰减速率大于初始状态或两个速率彼此之间的衰减速率大于初始状态时，光泵仍保持最佳状态。预计目前的工作将在遇到此类系统的各种量子信息处理任务中找到应用。
We use optimal control theory to show that for a closed $Λ$-system where the excited intermediate level decays to the lower levels with a common large rate, the optimal scheme for population transfer between the lower levels is actually optical pumping. In order to obtain this result we exploit the large decay rate to eliminate adiabatically the weakly coupled excited state, then perform a transformation to the basis comprised of the dark and bright states, and finally apply optimal control to this transformed system. Subsequently, we confirm the optimality of the optical pumping scheme for the original closed $Λ$-system using numerical optimal control. We also demonstrate numerically that optical pumping remains optimal when the decay rate to the target state is larger than that to the initial state or the two rates are not very different from each other. The present work is expected to find application in various tasks of quantum information processing, where such systems are encountered.
