Millikelvin cooling of an optically trapped microsphere in vacuum
Millikelvin cooling of an optically trapped microsphere in vacuum
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DOI：
10.1038/nphys1952
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发表时间：
2011-07-01
期刊：
影响因子：
19.6
通讯作者：
Raizen, Mark G.
中科院分区：
文献类型：
--
作者：
Li, Tongcang;Kheifets, Simon;Raizen, Mark G.
近年来，微机械谐振器在其质心运动中朝向量子力学基态的冷却已经迅速发展（1-8）。这项工作是创造“薛定谔猫”，宏观观测量的量子叠加，以及研究它们的退相干破坏的重要一步。在这里，我们报告的光学捕获的玻璃微球在真空中具有高的振荡频率，和冷却的质心运动从室温到最低温度约1.5 mK。这种新的系统消除了夹持杠杆固有的物理接触，并可以允许从室温（9-15）的地面状态冷却。更重要的是，光阱可以关闭，允许微球在冷却后在真空中自由下落（15）。这是研究引力态约化的理想方法（16-19），这是广义相对论和量子力学之间明显冲突的表现（16，20）。在真空中冷却的光学捕获物体也可以用于在小尺度上搜索非牛顿引力（21），测量单个空气分子的影响（14），甚至产生活生物体的薛定谔猫（9）。
Cooling of micromechanical resonators towards the quantum mechanical ground state in their centre-of-mass motion has advanced rapidly in recent years(1-8). This work is an important step towards the creation of 'Schrodinger cats', quantum superpositions of macroscopic observables, and the study of their destruction by decoherence. Here we report optical trapping of glass microspheres in vacuum with high oscillation frequencies, and cooling of the centre-of-mass motion from room temperature to a minimum temperature of about 1.5 mK. This new system eliminates the physical contact inherent to clamped cantilevers, and can allow ground-state cooling from room temperature(9-15). More importantly, the optical trap can be switched off, allowing a microsphere to undergo free-fall in vacuum after cooling(15). This is ideal for studying the gravitational state reduction(16-19), a manifestation of the apparent conflict between general relativity and quantum mechanics(16,20). A cooled optically trapped object in vacuum can also be used to search for non-Newtonian gravity forces at small scales(21), measure the impact of a single air molecule(14) and even produce Schrodinger cats of living organisms(9).