强耦合多模光力学系统的量子动力学及其在量子信息处理中的应用

Optomechanics, an emerging field focusing on the interaction between light and mechanical objects, has many important applications in basic science and highly sensitive measurements. A multimode optomechanical setup is importantly used for studying nonlinear interaction between multiple mechanical oscillators and multiple optical fields. Compared with standard optomechanical setup involving only single mechanical mode and single optical mode, it possesses more degrees of freedom for optomechanical control and thus provides a better way for studying optomechanical interaction. Recently, great advances have been made in optomechanical experimental research. The mechanical oscillators with micro- or nano-structure were successfully cooled down to the quantum ground state, which paves the way for exploring quantum behavior of mechanical vibration under the standard quantum limit, for preparation and manipulation of acoustic nonclassical states, and for optomechanical quantum information processing. Meanwhile, to achieve coherent control of a photon-phonon interaction system, another important goal in this field is to realize strong coupling between light field and mechanical oscillator, which may be reached in the near future. Thus, it is interesting and important to start looking into multimode optomechanical systems in the strong coupling regime that proposed in this project. The quantum dynamics of the systems near the quantum ground state influenced by reservoir will be studied. The preparation, detection, and manipulation of nonclassical states for mechanical oscillators will be discussed as well. Beyond these, we will consider how to prepare and detect entanglement among multiple multimode optomechanical setups, and discuss its utilization in quantum information processing, which in principle can be experimental interests.

光力学是研究光与机械振动相互作用的一门学科，它在基础研究和精密测量领域都有重要应用。多模光力学系统是研究多个机械振子与多个光场之间相互作用的装置，相对于只有单个机械振动模和单个光场模的标准装置它拥有更多可操控的自由度，因此为研究光机械相互作用提供了更好的途径。最近，光力学实验研究取得了突破，具有微纳米结构的机械振子成功被冷却到量子基态，为研究量子极限条件下机械振动的量子特性、声波非经典态的制备与操控和光机械量子信息处理铺平了道路。同时，人们还在不断努力实现光与机械振子的强耦合相互作用，以实现对光子－声子系统的相干控制，该物理条件很可能在不久后实现。因此，在本项目中，我们对强耦合多模光力学系统展开研究具有重要意义。我们将研究在库环境影响下系统处于量子基态附近时的量子动力学，探讨非经典态的制备、探测与操控，研究多个光力学系统量子纠缠态的制备和探测方法及其在量子信息处理中的应用，对实验提供指导。

光力学是研究光与机械振动相互作用的一门学科，它在基础研究和精密测量领域都有重要应用。多模光力学系统是研究多个机械振子与多个光场之间相互作用的装置。利用多模系统，人们在实验上已经观察到单模系统中不存在的新物理效应。我们研究了光学腔中悬挂SiN介电薄膜的双模光力学装置中实现机械振子自激振荡（声子激光）的非线性效应。我们讨论了由光学振荡模式所构成的两能级系统的Landau－Zener跃迁对机械振子动力学反作用所诱导的自激振荡的影响，同时给出了机械振子的多稳态与实际实验参数之间的联系。该理论同样适用于其他类似的光力学系统或纳米机械系统，如纳米机械装置或微波装置与超导库柏对、电流驱动双量子点结构或单电子存储器的耦合系统等。我们研究了两个相互耦合的双模光力学系统在外加周期性调制泵浦激光的驱动下的量子动力学。我们发现在稳态条件下，振子系统的动力学将与驱动激光调制周期相同。与没有调制的情况相比，振子之间的纠缠可以在更宽泛的参数和更高的库温度条件下得到增强，同时我们推导出了弱耦合条件下的最佳调制频率。此外，我们开展了利用里德堡原子系统进行量子信息处理的研究，试图将偶极－偶极相互作用原子系统与光力学系统相复合。