通过酉变换和辅助态测量实现两比特和三比特纯态的纠缠检测
Entanglement Detection for Two-Qubit and Three-Qubit Pure States via Unitary Transformations and Ancilla State Measurements
AI总结：
本文针对量子纠缠检测问题，基于酉变换和辅助测量提出量子电路方案，可直接测量两体并发度和三体3 - 缠结纠缠度量，无需全量子态层析成像，为纠缠特性实验表征及多体纠缠资源应用奠定基础。
AI中文摘要：
量子纠缠是量子力学的基本特征，也是实现长距离量子通信和可扩展线性量子计算的核心资源。因此，纠缠的精确检测和定量是量子信息理论中的一个基本且关键的问题。目前，核心纠缠参数的高效直接测量方案仍不完善。本文基于酉变换和辅助测量，提出了一组能够直接测量两体并发度和三体3 - 缠结纠缠度量的量子电路方案。通过引入辅助量子比特并构建特定的受控酉操作，将两种纠缠度量的解析表达式映射到量子电路输出态的测量概率上，无需进行全量子态层析成像就能实现对两体和三体纠缠的高效直接定量测量。这项工作为纠缠特性的实验表征提供了可行的技术路线，为多体纠缠资源在量子信息处理中的实际应用奠定了基础。
英文摘要：
Quantum entanglement is the fundamental hallmark of quantum mechanics and a core resource for realizing long-distance quantum communication and scalable linear quantum computing. Accordingly, the precise detection and quantitative quantification of entanglement constitute a foundational and critical problem in quantum information theory. To date, researchers have proposed numerous sufficient conditions for entanglement detection as well as a variety of entanglement measures to characterize the entanglement strength of quantum states; nevertheless, efficient and direct measurement schemes for core entanglement parameters remain underdeveloped. Based on unitary transformations and auxiliary measurements, this paper proposes a set of quantum circuit schemes capable of directly measuring the bipartite concurrence and the tripartite 3-tangle entanglement measure. By introducing auxiliary qubits and constructing specific controlled unitary operations, the proposed scheme maps the analytical expressions of the two entanglement measures onto the measurement probabilities of output states from quantum circuits. It enables efficient and direct quantitative measurement of bipartite and tripartite entanglement without performing full quantum state tomography. This work provides a feasible technical route for the experimental characterization of entanglement properties and lays a groundwork for the practical deployment of multipartite entanglement resources in quantum information processing.
