多光子多自由度超并行拒错量子计算研究

Quantum computation is one of important applications of quantum information, and it promises to increase substantially the efficiency of solving certain computationally demanding problems like searching databases and factoring large integers. In contrast with the tranditional quantum computing with many qubits encoding on one degree of freedom only, the hyper-parallel quantum computing in N degrees of freedom increases the channel capacity, reduces the resource by 1-1/N, and robusts against the decoherence caused by their environments. The artificial atom is one of the promising candidates for qubit because of their ultralong coherence time, scalability and flexible controllability, and it has been received great attention. My study is focused on designing compact quantum circuits for implementing error-rejecting hyper-parallel quantum computing via the artificial atoms coupled to resonators based on imperfect single-photon input-output process, including: (1) Error-rejecting quantum circuit for implementing hybrid hyper-parallel universal gates on multi-photon-matter system. (2) Heralded robust multi-photonic-qubit quantum computing with multiple degrees of freedom. (3) Implementation of multi-spin-qubit hyper-parallel quantum computing on solid-state systems through cavity-assisted interactions. Our schemes with high fidelities and high efficiencies will be helpful in hyper-parallel quantum computing and high-capacity quantum communication.

量子计算是量子信息的重要研究内容，它能加速计算速度，解决部分经典计算无法解决的难题。基于多自由度量子系统的超并行量子计算既能增加信道容量、节省资源，又能更好地抵抗光子损耗噪声影响，具有重要的科学意义。人工原子具有相对较长的相干时间和可扩展的优点，是量子计算机理想载体之一，是当今量子信息研究的热点之一。本项目将对基于人工原子非理想情形下的超并行量子计算展开深入研究，包括对光学不完美输入-输出免疫、对不同子系统同时进行独立操作、不受强耦合的限制等实用条件下,研究两个及其多个自由度量子系统的超并行量子计算，具体研究内容包括：(1)多光子与人工原子间超并行杂合拒错量子计算；(2)以人工原子为指示，对光学不完美输入-输出免疫的多光子多自由度超并行光量子计算；(3)多自旋超并行固态量子计算。通过这一研究，争取得到高保真度和高效率的超并行量子计算方案，对超并行量子计算和高容量量子通信研究有所帮助。

超并行量子信息处理是当今国际研究的热点，并以其独特的性质引起越来越多研究者的关注。本项目紧密联系实验，对并行和超并行量子信息处理中的部分问题展开深入研究，研究基于人工原子，各种环境下并行和超并行光量子计算、量子算法、量子光学器件构建的思路和方法，并获得一些有创新性的研究成果：(1) 结合单光子多自由编码，研究多自由度量子refined Detuch-Jozsa算法；(2) 利用人工原子，提出普适multi-qubit门的构建方法，且普事参数可控；(3) 在不完美物理系统下，设计鲁棒的超并行光量子信息处理和量子光学器件方案；我们方案具有信道容量高、环境噪声影响小、量子并行性强、资源消耗少、对不完美系统鲁棒等优点。方案应用于超并行量子计算，服务于超并行远程量子通信。