Sideband cooling of molecules in optical traps
Sideband cooling of molecules in optical traps
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DOI：
10.1103/physrevresearch.2.013251
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发表时间：
2019-10
影响因子：
4.2
通讯作者：
L. Caldwell;M. Tarbutt
中科院分区：
文献类型：
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作者：
L. Caldwell;M. Tarbutt
边带冷却是将原子冷却到光阱基态的常用方法。将同样的方法应用于分子需要克服许多挑战。强张量斯塔克位移的分子导致的光阱势，和相应的陷阱频率，强烈依赖于旋转，超精细和塞曼状态。因此，跃迁频率取决于运动量子数，并且存在额外的加热机制，其中任何一种对于有效的边带冷却方案都可能是致命的。我们发展了态相关势中边带冷却的理论，导出了光子散射加热的表达式。我们计算的交流斯塔克位移的分子状态的存在下的磁场，并为任何极化。我们表明，边带冷却的复杂性可以大大降低通过施加一个大的磁场，以消除电子和核自旋自由度的问题。我们考虑需要多大的磁场，表明加热可以得到足够好的管理，并提出了一个简单的食谱冷却到基态的运动。
Sideband cooling is a popular method for cooling atoms to the ground state of an optical trap. Applying the same method to molecules requires a number of challenges to be overcome. Strong tensor Stark shifts in molecules cause the optical trapping potential, and corresponding trap frequency, to depend strongly on rotational, hyperfine and Zeeman state. Consequently, transition frequencies depend on the motional quantum number and there are additional heating mechanisms, either of which can be fatal for an effective sideband cooling scheme. We develop the theory of sideband cooling in state-dependent potentials, and derive an expression for the heating due to photon scattering. We calculate the ac Stark shifts of molecular states in the presence of a magnetic field, and for any polarization. We show that the complexity of sideband cooling can be greatly reduced by applying a large magnetic field to eliminate electron- and nuclear-spin degrees of freedom from the problem. We consider how large the magnetic field needs to be, show that heating can be managed sufficiently well, and present a simple recipe for cooling to the ground state of motion.