Du Fang-Fang, Ma Ming, Tan Qiu-Lin
Key Laboratory of Micro/nano Devices and Systems, Ministry of Education, North University of China, Taiyuan, 030051, China.
Sci Rep. 2025 Jan 20;15(1):2505. doi: 10.1038/s41598-025-85673-0.
As the hyperentanglement of photon systems holds lots of remarkable applications for enhancing channel capacity with less quantum resource, the interconversion of various hyperentangled states warrants in-depth investigation and becomes a vital work for quantum information technologies. Here we realize completely mutual conversions between spatial-polarization hyperentangled Knill-Laflamme-Milburn state and hyperentangled W state for three-photon systems, resorting to hyperparallel quantum control gates and the practical nonlinear interaction of nitrogen-vacancy centers coupled with whispering-gallery-mode microresonators. The hyperparallel quantum gates, i.e., hyperparallel controlled-not and controlled-swap gates, are fundamental prerequisites for realizing interconversions of two hyperentangled states in a deterministic way. The fidelities of these conversion processes are robust and their efficiencies are also high due to fewer nonlinear interactions and errors heralded by the response of detectors, which intensify comprehending the properties of hyperentanglement.
由于光子系统的超纠缠在利用更少的量子资源增强信道容量方面有许多显著应用，各种超纠缠态的相互转换值得深入研究，并成为量子信息技术的一项重要工作。在此，我们借助超并行量子控制门以及氮空位中心与回音壁模式微谐振器耦合的实际非线性相互作用，实现了三光子系统的空间 - 偏振超纠缠Knill - Laflamme - Milburn态与超纠缠W态之间的完全相互转换。超并行量子门，即超并行控制非门和控制交换门，是以确定性方式实现两种超纠缠态相互转换的基本前提。这些转换过程的保真度很高，并且由于探测器响应预示的非线性相互作用和误差较少，其效率也很高，这加深了对超纠缠特性的理解。
