Ground state cooling and quantum backaction of a mechanical oscillator - GSC

拟议的研究计划建立在申请人在“加州理工学院”的博士论文期间开发的超高Q单片微谐振器的基础上。这些微谐振器在更长的时间内对微尺度的光提供了前所未有的限制，并开启了从非线性光学、量子光学到生化传感的许多芯片实验室应用。这一提议涉及到利用超高Q光学微腔作为载体来演示机械振子冷却到其量子基态。到目前为止，机械物体的基态冷却已经启发了研究人员几十年，但到目前为止还没有实现。去年，几个小组(包括Garching MPQ的申请者小组)首次展示了微机械振荡器的辐射压力(激光)冷却。就在发表后不久，其他几个小组报告了使用辐射压力来冷却克级反射镜和悬臂梁，这导致了实现机械振荡器基态冷却(GSC)的新努力，如图1所示。这项提议要求在低温设备和激光系统方面的必要基础设施-目前没有任何其他拨款涵盖-允许在马克斯·普朗克量子光学研究所实现这一目标，并跟上这个快速发展的国际领域的步伐。这项研究可能导致第一次证明一个拥有~1022个原子的宏观物体的基态冷却，这是迄今为止从未被证明的，也可能是第一次证明有质量动力的量子反作用和压缩。从概念的角度来看，这项研究可以展示一个机械的、宏观的物体是如何揭示量子力学行为的，这可能为研究经典量子边界或准备机械运动的非经典状态打开可能性。

The proposed research program builds on the previously developed ultra-high-Q monolithic micro-resonators by the applicant during his dissertation at the “California Institute of Technology”. These micro-resonators offer unprecedented confinement of light in microscale volumes for extended amounts of time and have opened many lab-on-chip applications ranging from nonlinear optics, quantum optic to biochemical sensing. This present proposal is concerned to use ultra-high-Q optical micro-cavities as vehicles to demonstrate cooling of a mechanical oscillator to its quantum ground state. So far ground state cooling of mechanical objects has inspired researchers for decades, but it has to date never been attained. Within the last year, several groups (including the applicants group at the MPQ in Garching) have demonstrated for the first time radiation pressure (laser) cooling of micro-mechanical oscillators. Only shortly after publication several other groups reported cooling of gram-scale mirrors and cantilevers using radiation pressure which has lead to a renewed effort towards achieving ground state cooling (GSC) of a mechanical oscillator, as summarized in figure 1. This proposal requests essential infrastructure in terms of low temperature equipment and a laser system - not presently covered under any other grant – to allow pursuing this goal at the Max Planck Institute of Quantum Optics and to keep pace with this rapidly moving international field. This research could result in the first demonstration of ground state cooling of a macroscopic object with ~1022 atoms, which has so far never been demonstrated as well as the first demonstration of pondermotive quantum back-action and squeezing. From a conceptual point of view, this research could show how a mechanical, macroscopic object reveals quantum mechanical behavior which could open the possibility to study the classical quantum boundary, or prepare non-classical states of mechanical motion.