量子态的精确测量与分辨实验研究

伴随着量子信息和量子计量学的实用化发展，更精确的量子态制备、操控和测量越来越重要，而这些都需要精确的量子态的测量与分辨技术作为基础。本项目将围绕如何实现量子态的测量与分辨方法的简化或者精度的提高等方面开展实验研究。利用矩阵直积态等方法在实验上首次实现测量复杂度随着比特数线性增长的量子态层析方法；改进量子态层析方法中现有重构算法，降低计算复杂度；结合自适应测量和反馈控制的方法，利用已知的部分信息优化下一次测量基的选择和资源的分配方式来提高测量精度，试图完成世界上首个两比特量子态的自适应测量实验研究。利用反馈控制和量子随机行走等方式实现量子态的精确分辨。探讨量子物理学基本原理对量子态精密测量与分辨中多参数估计精度的影响，并实验验证相关精度下界。本项目围绕量子信息和量子计量学前沿重要问题展开研究，其成果必将推动量子信息和量子计量学的进一步发展。

With the development of quantum information and quantum metrology and their aim to practicality, we need more and more precise quantum state preparation, operator and measurement, which should be based on measuring and discriminating quantum state with high precision. Here we propose to simplify the methods of quantum state measurement and discrimination and improve the precision of it. We will use the matrix product state to realize the first quantum state tomography with that the measurement bases are increased linearly with number of qubits. We will try to reduce the complexity of quantum state reconstruction and reconstruct the density matrix of the maximum number of qubits. We will optimize the choice of measurement bases and distribution of quantum resource by using adaptive measurement and quantum feedback control to improve precision, and try to propose and realize the first adaptive quantum state tomography scheme for two qubits states. We will use quantum feedback control and quantum random walk to discriminate.quantum signals with precision beating standard quantum limit or more precisely. We will investigate how the basic principle of quantum mechanics affects the precision of measurement and discrimination of quantum state, and demonstrate the lower bound of multi-parameter. The success finish of this project will promote the development of quantum information and quantum metrology.