The generation and storage of spin squeezing is an attractive topic in quantum metrology and the foundation of quantum mechanics. The major models to realize the spin squeezing are the one- and two-axis twisting models. Here, we consider a collective spin system coupled to a bosonic field, and show that proper constant-value controls in this model can simulate the dynamical behavior of these two models. More interestingly, a better performance of squeezing can be obtained when the control is time varying, which is generated via a reinforcement learning algorithm. However, this advantage becomes limited if the collective noise is involved. To deal with this, we propose a four-step strategy for the construction of a type of combined controls, which include both constant-value and time-varying controls, but performed at different time intervals. Compared to the full time-varying controls, the combined controls not only give a comparable minimum value of the squeezing parameter over time, but also provide a better lifetime and larger full amount of squeezing. Moreover, the amplitude form of a combined control is simpler and more stable than the full time-varying control. Therefore, our scheme is very promising to be applied in practice to improve the generation and storage performance of squeezing.

中文翻译：

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通过学习辅助的最佳控制来生成和存储自旋压缩

自旋压缩的产生和存储在量子计量学中是一个有吸引力的话题，也是量子力学的基础。实现自旋挤压的主要模型是一轴和二轴扭曲模型。在这里，我们考虑耦合到玻色子场的集体自旋系统，并表明该模型中适当的恒定值控件可以模拟这两个模型的动力学行为。更有趣的是，当控件随时间变化时，可以通过增强学习算法生成更好的压缩性能。然而，如果涉及集体噪声，则该优点变得有限。为了解决这个问题，我们提出了一种构建组合控件类型的四步策略，该组合控件既包含恒定值控件，也包含时变控件，但执行时间间隔不同。与完全随时间变化的控件相比，组合控件不仅随时间推移提供可比的最小挤压参数值，而且还提供了更好的寿命和更大的完全挤压量。而且，组合控制的幅度形式比全时变控制更简单，更稳定。因此，我们的方案非常有希望在实践中用于提高挤压的产生和存储性能。