Buffer-Gas Cooling of a Single Ion in a Multipole Radio Frequency Trap Beyond the Critical Mass Ratio.
Buffer-Gas Cooling of a Single Ion in a Multipole Radio Frequency Trap Beyond the Critical Mass Ratio.
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多极射频阱中单个离子的缓冲气体冷却超出临界质量比。
DOI：
10.1103/physrevlett.116.233003
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发表时间：
2015
影响因子：
8.6
通讯作者：
M. Weidemüller
中科院分区：
文献类型：
--
作者：
B. Höltkemeier;P. Weckesser;Henry López;M. Weidemüller
我们从理论上研究了浸没在空间局域缓冲气体中的囚禁离子的动力学。对于均匀的缓冲气体，只有当缓冲气体原子的质量低于临界值时，离子的能量分布才达到稳定的平衡。这种限制可以通过使用多极阱结合空间受限的缓冲气体来克服。使用一个广义模型的离子与缓冲气体原子的弹性碰撞，离子的能量分布的数值确定为任意的缓冲气体分布和陷阱参数。发现了三个区域，其特征在于离子的平衡能量分布的解析形式，最终的离子温度可以通过精确地减小缓冲气体的空间延伸和有效离子阱深度（强迫交感冷却）而达到毫开尔文区域。
We theoretically investigate the dynamics of a trapped ion immersed in a spatially localized buffer gas. For a homogeneous buffer gas, the ion's energy distribution reaches a stable equilibrium only if the mass of the buffer gas atoms is below a critical value. This limitation can be overcome by using multipole traps in combination with a spatially confined buffer gas. Using a generalized model for elastic collisions of the ion with the buffer-gas atoms, the ion's energy distribution is numerically determined for arbitrary buffer-gas distributions and trap parameters. Three regimes characterized by the respective analytic form of the ion's equilibrium energy distribution are found. Final ion temperatures down to the millikelvin regime can be achieved by adiabatically decreasing the spatial extension of the buffer gas and the effective ion trap depth (forced sympathetic cooling).