量子开系统的涨落效应及非马尔科夫时间演化

It is an important problem in the studies of quantum information processing and quantum computing to take into account effects of quantum fluctuations and thermal fluctuations induced by the interaction between solid-state quantum systems and their environments. We use a system plus many-degree-of-freeedom environment model to find its physicical properties in a non-Markovian environment and also to give non-Markovian dynamical characters. The main content of our project is as follows,(1) we should develop a method based on unitrary transformation to explore open quantum systems; (2) by this method, we study interesting physical processes of solid state quantum systems: decoherence, dephasing, dissipation, entanglement and disentanglement, etc, and also give the effects of quantum and thermal fluctuations on those processes; (3) we try to find some accessible schemes and methods to control the interaction between quantum systems and their dissipative environments. The developed analytical method in this project is totally different from the traditonal approximate methods, such as rotating-wave approximation method, Bloch-Redfield method. It can correctly give the effects of quantum fluctuations on energy spectrum, and explore finite temperature non-Markovian dynamical characters in the short time evolution and long time limit. The developed method is able to extend to study quantum dynamics of more complex many-body quantum system, and also investigate various kinds of environments: quantum structureless and structural environment. It is significant for this project to study the properties of open quantum systems and understand the transient dynamics in current solid-state quantum experiments.

固态量子开系统与环境相互作用引起的量子涨落效应和热涨落效应是量子信息处理和量子计算研究中的重要问题。本课题以固态量子系统与多自由度环境相互作用的模型为研究对象,试图揭示在非马尔科夫环境中系统的物理性质和非马尔科夫动力学演化特征。本课题主要内容：(1)发展以幺正变换为基础的开放量子系统的理论方法；(2)采用该方法研究固态量子系统中的物理过程、量子涨落和热涨落效应（退相干、弛豫、耗散、纠缠等）；(3)研究调控量子系统与耗散环境相互作用的机制与方法。本课题发展的解析方法与传统近似方法 (旋转波近似方法、Bloch-Redfield方法等）截然不同，既能正确地给出能谱的量子涨落效应,还能探究短时间和长时间的有限温度非马尔科夫动力学特征。该方法能推广研究复杂的多体量子系统，同时适用于研究无结构和有结构的环境。本课题对研究开放量子系统的物理性质和认识当前固态量子实验中短时动力学有重要意义。

固态量子开系统与环境相互作用引起的量子涨落效应和热涨落效应是量子信息处理和量子计算研究中的重要问题。本课题以固态量子系统与多自由度环境相互作用的模型为研究对象,揭示在耗散环境中系统的物理性质和非马尔科夫动力学演化特征。我们发展以幺正变换为基础的开放量子系统的理论方法和周期驱动的量子系统解析方法，为探索强耗散物理、偏执调制和外场操控研究提供研究手段；采用上述方法研究各量子系统（双量子比特耗散系统、自旋玻色子模型、双光子量子Rabi模型等）中的基态和激发态，驱动耗散系统稳态和光谱，量子动力学、量子涨落和热涨落效应（退相干、耗散、纠缠等物理性质）；研究调控量子系统与耗散环境相互作用的机制与方法。我们利用了库工程思想，提出了针对耗散腔的量子调控方案，使得双量子比特之间的量子纠缠与信息有效保存；通过研究耗散环境中量子比特的芝诺效应，发现了环境的记忆会引起衰减率的时间振荡变化（传统的芝诺效应衰减率为常数）。本课题对研究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。