AI 中文总结
该研究基于林德布拉德主方程模拟正电子素激光冷却，考虑原子相干性，定量预测冷却后的动量分布，发现可通过速度选择相干布居俘获实现反冲以下冷却。
AI 中文摘要
我们提出了正电子素（Ps）激光冷却的一种公式化方法及数值结果，该方法基于林德布拉德主方程，追踪Ps原子密度矩阵的时间演化，因此能考虑原子相干性，这对描述Ps与Shu等人开发的系统产生的短激光脉冲序列的相互作用至关重要[K. Shu等人，《物理评论A》第109卷，043520（2024）]。利用该公式，我们计算了各内部态和动量态的布居数时间演化，从而定量预测激光冷却后的动量分布。我们展示了内部态布居数和动量分布的代表性时间演化，以及用于优化冷却效率的激光参数的全面扫描。模拟分布的一个显著特征是通过速度选择相干布居俘获实现的反冲以下冷却，这是量子力学处理所捕捉到的一种相干效应。
英文摘要
We present a formulation and numerical results for positronium (Ps) laser cooling. The formulation is based on the Lindblad master equation and follows the time evolution of the density matrix of Ps atoms. It therefore accounts for atomic coherence, which is necessary to describe the interaction of Ps with the train of short laser pulses generated by the system developed by Shu $\textit{et al.}$ [K. Shu $\textit{et al.}$, Phys. Rev. A $\textbf{109}$, 043520 (2024)]. Using this formulation, we calculate the time evolution of the populations in each internal and momentum state and thereby quantitatively predict the momentum distribution after laser cooling. We present the representative time evolution of the internal-state populations and momentum distribution, together with a comprehensive scan of the laser parameters used to optimize the cooling efficiency. A prominent feature of the simulated distributions is sub-recoil cooling through velocity-selective coherent population trapping, a coherent effect captured by the quantum-mechanical treatment.
Comments8 pages, 3 figures
