谐振子的薛定谔猫态不仅对于量子力学基本问题的探索具有重要意义，而且在量子信息处理中具有实际应用价值。本项目拟在电路量子电动力学（QED）系统中研究微波场薛定谔猫态的操控,并探讨其量子非定域性。首先，基于超导比特与量子化微波场及经典脉冲的相互作用，设计适当的物理过程，使之在不破坏一个微波场薛定谔猫态的叠加成分（相干态）的前提下，能解除微波场与热库之间的纠缠，从而恢复猫态的量子相干性。在此基础上，研究双模薛定谔猫态的纠缠随时间的退化过程，并提出这种纠缠的保护方案。进一步构造有效的猫态比特旋转算符及相应的贝尔算符，以得到介观尺度的双模及多模薛定谔猫态对贝尔不等式的最大违背，并在电路QED系统中设计适当的方案以观测相应的量子非定域性。然后，提出有效方案以实现两个或更多的编码于猫态的微波光场比特间的受控量子相位门以及基于这类比特的量子搜索算法。

Schrödinger cat states of oscillators not only are important for exploration of fundamental issues of quantum mechanics, but also have practical applications in quantum information processing. In this project, we will study the manipulation of Schrödinger cat states of microwave fields in circuit quantum electrodynamics (QED) systems, and investigate their quantum nonlocality. First, based on the interaction of a superconducting qubit with a quantized microwave field and classical pulses, we will design a physical process, which can undo the entanglement between the microwave field and the reservoir without destroying the superposing components forming a Schrödinger cat state of the field, reviving the quantum coherence of the cat state. On this basis, we will study the entanglement degration process of two-mode Schrödinger cat states, and propose a scheme for the protection of this entanglement. Then we will further construct effective rotation operators and Bell operators for cat state qubits to obtain the maximal violations of Bell inequalities for two-mode and multimode Schrödinger cat states with mesoscopic sizes, and propose schemes for observing the corresponding quantum nonlocality in circuit QED systems. Finally, we will propose efficient schemes for realizing controlled quantum phase gates for two or more qubits encoded in cat states of microwave fields and the quantum search algorithm based on this kind of qubits.