强驱动量子开系统动力学及其相干性调控

It is an important problem in the studies of quantum information processing and quantum computing to take into account evolution of quantum states induced by the interaction between solid-state quantum systems under a driving field and their environments. We investigate a model consisting of a driven quantum system and many-degree-of-freeedom environment to find the physicical properties of driven dissipative quantum systems and also to give the characters of driven dynamics. The main content of our project is as follows,(1) we should develop a method based on unitrary transformation to explore open quantum systems controlled by time-dependent driving fields; (2) by this method, we study interesting interacting physical processes of driving and dissipation in solid state quantum systems, the properties of stable states, and spectral features; (3) we try to find some accessible schemes and methods to control the interaction between quantum systems and their dissipative environments i.e. suppress decoherence and avoid disentanglement. The developed analytical method in this project is totally different from the traditonal approximate methods, such as rotating-wave approximation method. It can correctly give the energy spectrum of quantum open systems under a peroidic driving, and explore driven dynamical characters of both transient states and stable states. The developed method is able to be extended to study quantum dynamics of both hybird quantum systems and more complex many-body system under strongly driving fields, and also investigate various kinds of environments: structureless and structural environments. It is significant for this project to study the properties of open quantum systems under periodic driving fields and understand the driven dynamics in current solid-state quantum experiments.

驱动场作用的固态量子开系统与环境相互作用引起的量子态演化是量子信息处理和量子计算研究中的重要问题。本项目以驱动量子系统与多自由度环境相互作用的模型为研究对象,试图揭示在固体环境中驱动耗散量子系统的物理性质和驱动动力学特征。本项目主要内容：(1)发展以幺正变换为基础的理论方法进行含时驱动场调控的开放量子系统研究；(2)采用该方法研究开系统中的驱动和耗散相互作用的物理过程、稳态性质和谱学行为；(3)研究调控量子系统和环境相互作用（抑制退相干或者退纠缠）的机制与方法。本项目发展的解析方法与传统近似方法 (旋转波近似方法等）截然不同，既能正确地给出周期外场作用下量子开系统的能谱,还能探究暂态和稳态驱动动力学特征。该方法能推广研究强驱动作用的复合量子系统和多体系统，同时适用于研究无结构和有结构的环境。本项目对研究周期驱动作用下开放量子系统的物理性质和认识当前固态量子实验中驱动动力学有重要意义。

驱动场作用的量子开系统与环境相互作用引起的量子态演化是量子信息处理和量子计算研究中的重要问题。本项目以驱动量子系统与多自由度环境相互作用的模型为研究对象，揭示在环境中驱动耗散量子系统的物理性质和驱动动力学特征。本项目发展了含时幺正变换解析方法，研究得到了强驱动系统的多谐波动力学效应，并揭示了拉比模型中几何相位的多谐波共振效应；采用合适的幺正变换来分析驱动耗散量子系统的反旋转波物理效应、双量子比特系统相干性布局、双自旋玻色子模型在欧姆谱等类型环境中的量子相变；采用合理的物理量来刻画描绘量子系统的相干动力学和纠缠动力学，计算频率调制拉比模型的荧光光谱等来揭示系统能谱性质，深入阐明在旋转波近似和非旋转波近似两种方法下量子态动力学和光谱的差异；深入揭示了开放量子系统下非马尔科夫动力学演化，给出库记忆效应对量子芝诺现象的影响。这些结果对研究周期驱动作用下开放量子系统的物理性质和认识当前固态量子实验中动力学有重要意义。