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

提出的研究计划是基于申请人在“加州理工学院”的论文期间开发的超高q单片微谐振器。这些微谐振器提供了前所未有的光在微尺度上的限制，延长了大量的时间，并开辟了许多芯片上的实验室应用，从非线性光学，量子光学到生化传感。本研究的目的是利用超高q光微腔作为载具来演示机械振荡器冷却到量子基态的过程。到目前为止，机械物体的基态冷却已经激励了研究人员几十年，但迄今为止还没有实现。去年，几个小组（包括加兴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。就在论文发表后不久，其他几个研究小组报道了利用辐射压力冷却克级反射镜和悬臂的研究，这导致了对实现机械振荡器基态冷却（GSC）的新努力，如图1所示。该提案要求低温设备和激光系统方面的基本基础设施-目前没有任何其他资助-允许马克斯普朗克量子光学研究所实现这一目标，并跟上这一快速发展的国际领域的步伐。这项研究可能会导致首次证明具有~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过的，以及首次证明了重动机量子反作用和压缩。从概念的角度来看，这项研究可以展示一个力学的宏观物体如何揭示量子力学行为，这可能为研究经典量子边界或制备非经典力学运动状态提供可能性。

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.