In recent demonstrations of the quantum charge-coupled device computer architecture, circuit times are dominated by cooling. Some motional modes of multi-ion crystals take orders of magnitude longer to cool than others because of low coolant ion participation. Here we demonstrate a new technique, that solves this issue by coherently exchanging the thermal populations of selected modes on timescales short compared to direct cooling. Using this method, which we call “phonon rapid adiabatic passage,” we can achieve subquanta temperatures from initial states with occupations as high as n¯∼200 quanta. Analogous to adiabatic rapid passage, we quasistatically couple these slow-cooling modes with fast-cooling modes using dc electric fields. When the crystal is then adiabatically ramped through the resultant avoided crossing, nearly complete phonon population exchange results. We demonstrate this on two-ion crystals, and show the indirect ground-state cooling of all radial modes—achieving an order of magnitude speedup compared to direct cooling. We also show the technique’s insensitivity to trap potential and control field fluctuations, and find that it still achieves subquanta temperatures starting as high as n¯∼200. Published by the American Physical Society 2024

中文翻译：

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使用 Phonon 快速绝热通道冷却捕获离子


在量子电荷耦合器件计算机架构的最新演示中，电路时间主要由冷却决定。由于冷却剂离子参与率低，多离子晶体的某些运动模式比其他运动模式需要比其他模式长几个数量级的时间。在这里，我们演示了一种新技术，与直接冷却相比，该技术通过在较短的时间尺度上连贯地交换选定模式的热群来解决这个问题。使用这种方法，我们称之为“声子快速绝热通过”，我们可以从初始状态实现亚量子温度，占用率高达 n ̄∼200 量子。类似于绝热快速通过，我们使用直流电场将这些慢冷却模式与快速冷却模式准静态耦合。当晶体然后绝热地通过由此产生的避免交叉时，几乎完全的声子种换结果。我们在双离子晶体上证明了这一点，并展示了所有径向模式的间接基态冷却——与直接冷却相比，速度提高了一个数量级。我们还展示了该技术对捕获电位和控制场波动的不敏感性，并发现它仍然可以达到高达 n ̄∼200 的亚量子温度。 美国物理学会 2024 年出版