arXiv 2012.077592020-12physics.atom-phquant-ph

原子-离子碰撞中交换冷却的直接观察

Direct observation of swap cooling in atom-ion collisions

Amir Mahdian, Artjom Krükow, Johannes Hecker Denschlag

备注：: 8 pages, 5 figures
DOI：: 10.1088/1367-2630/ac0575

摘要：

与冷粒子的碰撞可以耗散热粒子的能量，因此可以用作冷却机制。动力学告诉我们，要使粒子冷却几个数量级，通常需要多次弹性碰撞，因为每次碰撞只带走一定比例的碰撞能量。最近，对于由热离子和冷原子组成的系统，已经提出了一种更快的冷却过程，其中在单个步骤中可以发生几个数量级的冷却。也就是说，在同核原子-离子碰撞中，电子可以共振地从超冷原子跳到热离子上，将冷原子转换为冷离子。在这里，我们演示了这样的交换冷却在一个直接的方式，我们实验观察如何一个单一的高能离子在冷原子云失去能量。为了对比交换冷却与标准的交感冷却，我们进行了相同的测量与异核原子-离子系统，交换冷却不能发生，并确实观察到不同的冷却动力学。从头算数值模型计算与我们的测量数据吻合良好，并证实了我们的解释。我们预期交换冷却在任何同核原子-离子碰撞中都相当普遍地发生。因此，它应该是一个无处不在的过程中的混合原子-离子气体和等离子体。此外，它为快速冷却应用提供了有趣的前景。

英文摘要：

Collisions with cold particles can dissipate the energy of a hot particle and therefore be exploited as a cooling mechanism. Kinetics teaches us that for a particle to be cooled down by several orders of magnitude, it will typically take many elastic collisions as each one only carries away a certain fraction of the collision energy. Recently, for a system consisting of hot ions and cold atoms, a much faster cooling process has been suggested where cooling over several orders of magnitude can occur in a single step. Namely, in a homo-nuclear atom-ion collision, an electron can resonantly hop from an ultracold atom onto the hot ion, converting the cold atom into a cold ion. Here, we demonstrate such swap cooling in a direct way as we experimentally observe how a single energetic ion loses energy in a cold atom cloud. In order to contrast swap cooling with standard sympathetic cooling, we perform the same measurements with a hetero-nuclear atom-ion system, for which swap cooling cannot take place, and indeed observe much different cooling dynamics. Ab initio numerical model calculations agree well with our measured data and corroborate our interpretations. We expect swap cooling to occur quite universally in any homo-nuclear atom-ion collision. It should therefore be a ubiquitous process in mixed atom-ion gases and plasmas. Furthermore, it offers interesting prospects for fast cooling applications.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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