电路QED系统中多能级超导人工原子的量子态操纵和测量

电路量子电动力学系统(QED)是最具竞争力的量子信息处理候选方案之一。在电路QED系统中二能级超导人工原子通常被用来作为量子信息的载体（量子比特）。由于超导人工原子可以被调制成具有反谐性很好的多能级结构，作为我们之前研究工作的延拓和深入，在本项目中我们将开展电路QED系统中多能级超导人工原子的量子态操纵和量子非破坏性测量等方面的研究。具体的研究内容包括：1）多能级超导人工原子的量子非破坏性测量及其应用于实现高效且最优化的量子态重构和验证量子力学基本原理；2）对多能级人工原子施加微波场来设计耗散过程，利用耗散作为一种资源来制备各种量子纠缠态，如Bell态、GHZ态、W态以及高维纠缠态；3）实现多能级人工原子的量子逻辑门和量子计算，探索通过调控耗散过程实现量子计算的新模式。本项目的研究不仅可以为未来量子信息技术的发展提供理论基础和实验依据，而且也可以为量子力学基本原理的验证提供新的途径。

Circuit quantum electrodynamics system (QED) is one of the most competitive candidates for quantum information processing. In circuit QED, two-level superconducting artificial atom is usually used as the carrier (qubit) of quantum information. Because superconducting artificial atom can be adjusted to own many energy levels with good anharmonicity, as an extension of our previous works, in this proposal we will investigate quantum state manipulation and quantum non-demolition measurement of multi-level superconducting artificial atom in circuit QED. Concrete research contents include: 1) quantum non-demolition measurement of multi-level superconducting artificial atom and its applications to realize high-efficiency and optimal quantum state tomography and test the basic principles of quantum mechanics; 2) Engineering dissipation by adding microwave fields on artificial atoms, using dissipation as a kind of resources to prepare various kinds of quantum entangled states, such as Bell state, GHZ state, W state, and high-dimensional entangled states; 3) Realizing quantum logic gates and quantum computing for multi-level superconducting artificial atom and exploring new model of quantum computing by engineering dissipation. The investigations of this proposal can not only provide theoretical and experimental foundations for the development of future quantum information technologies, but also provide new approaches for testing the basic principles of quantum mechanics.