磁场-重力悬浮力学振子的反馈冷却

Feedback Cooling of a Magnetic-Gravity Levitated Mechanical Resonator

悬浮力学振子是近年来发展起来的新型高灵敏的力学探测手段,相比于固态力学振子,悬浮系统由于和外部环境完全没有物理接触,有着非常高的品质因子,在弱力测量,波函数塌缩测量等方面非常具有潜力。讨论了反馈冷却的机制,利用NdFeB永磁体对乙二醇600液滴实现了抗磁悬浮,并且用一个微线圈对其两个振动模式进行了反馈冷却,在常温300 K和真空环境10^(-5)mbar中达到了实现了几百mK量级的冷却。实验结果与理论预测的最低有效温度吻合,为将来深入研究宏观量子现象提供了一个良好的平台。

Levitated nano mechanical resonator is a newly developed detection method of high-precision measurement.Thanks to the high factor,it is promising in a wide range of fields including weak force detection,wave function collapse measurement,and so on.The mechanism of feedback cooling is discussed in this paper.In addition,NdFeB permanent magnets are used to perform diamagnetic levitation of polyethylene glycol 600.In an experiment in this paper,a micro coil is used for feedback cooling for two modes to reach hundreds of Kelvin under 300 K and 10^(-5) mbar vacuum condition.The experiment result agrees with the theoretical lowest effective temperature,which paves way for a further research on macro quantum phenomena.