开放原子-光力学系统中的量子关联

It's quite difficult to observe quantum effects at the macroscopic scale. However, quantum mechanics intrinsically shows no limitation to describe large-scale systems. Therefore, preparing macroscopic quantum state is of vital importance for understanding fundamental issues in quantum mechanics, such as decoherence and the quantum-to-classical transition. Optomechanics provides an ideal platform to generate and control quantum mesoscopic/macroscopic states. In hybrid atom-assisted optomechanical systems, atoms induce an additional nonlinear effect, which enhances the optomechanical interaction and boosts the cooling of the mechanical motion, moreover, results in abundant quantum phenomenon. Our subject focuses on the following parts: 1) the quantum correlation in optomechanical systems that coupled with atomic resemble, such as quantum entanglement, nonlocality, etc.; 2) the preparation of optical and mechanical non-classical state based on the above system; 3) quantum effects mentioned above with different input field (coherent light and squeezing light), different optomechanical structure (oscillating mirror and membrane inside), and different atomic model(two-level and multi-level). Such research is aiming at understanding those quantum mechanism in atomic optomechanical systems and will be instructive for experimental realization of creating micro-macro entanglement and generating a macroscopic quantum state (nonclassical state of the mechanical oscillator) and a new kind of squeezing state of the cavity field.

在宏观尺度下一般很难观测到量子效应，但量子力学从本质上说并没有任何尺度上的限制，因此，制备宏观量子态对拓展量子力学基本问题的认识，如消相干、量子-经典跃迁等，具有重要意义。光力学系统为产生和控制宏观/介观量子态提供了一个理想的平台。当原子与光力学系统耦合时，会激发更强的非线性效应，增强光力相互作用，冷却力学振子，呈现出丰富的量子现象。本课题拟开展如下研究工作：1.原子系综与光力学系统耦合过程中的量子关联，如量子纠缠、非局域性等；2.基于上述过程的光场非经典态和力学振子非经典态的制备；3.不同输入光场（相干光和压缩光）、不同光力学结构（振动腔镜和插入薄膜）、不同原子模型（二能级原子和多能级原子）对上述结果的影响。通过这项研究，明确原子与光力学系统耦合中的量子机制，并为进一步实验产生宏观-微观量子纠缠、实验制备宏观量子态（力学振子的非经典态等）和新型光场压缩态提供理论依据。

量子纠缠是量子计算、量子信息传输和构建量子网络的重要量子资源。基于本项目的资助我们主要完成了以下工作：研究了包含悬浮纳米球的腔光力学系统并提出了基于此系统实验检验塌缩噪声的方案；研究了在光力学系统中放置OPA晶体对光模之间纠缠的增强以及这种增强相应的参数依赖关系；提出了基于空间模式梳产生大尺度Cluster纠缠态和基于光学频率梳平行产生31个连续变量三组份纠缠态的方案。这些理论研究均建立在实验可行的参数下并得到了预想的结果，这些研究结果对完善宏观领域的量子力学、实现不同量子节点之间的纠缠及其增强并进一步实现量子网络的构建、结合波分/空分/时分复用技术实现大容量量子计算等等均具有重要的指导意义。