共振荧光中多光子纠缠的观测
Observation of multiphoton entanglement in resonance fluoresce
- University of Science and Technology of China（中国科学技术大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
实验揭示共振荧光的多光子散射本质，产生真正的能量-时间纠缠，并利用该纠缠源实现量子秘密共享，为多光子纠缠态生成提供简单途径。
AI中文摘要：
共振荧光是单个两能级量子发射体与近共振相干光相互作用的过程，作为典型的光与物质相互作用，是量子光学的基石。共振荧光中的量子现象已通过单光子和双光子过程得到解释；然而，由单个两能级原子与更高光子数相互作用产生的物理过程在实验上仍未得到探索。在此，我们在实验上揭示了共振荧光的固有属性——多光子散射本质，该本质自然地导致多光子纠缠的产生。通过获取腔量子电动力学系统发射场中的量子涨落，我们解析了来自单个两能级原子的三阶和四阶光子散射事件。在三光子分量中，散射光子被证明是真正的能量-时间纠缠，这通过违反Svetlichny不等式得到验证。作为应用演示，我们利用该纠缠光子源实现了一个量子秘密共享（QSS）协议。我们的研究完善了共振荧光的描述框架，并拓宽了其研究范围，同时为量子信息处理和量子计量学中多光子纠缠态的产生建立了一条根本性的简单途径。
英文摘要：
Resonance fluorescence, the process in which a single two-level quantum emitter interacts with a near-resonant coherent light, is a cornerstone of quantum optics as a paradigmatic light-matter interaction. Quantum phenomena in resonance fluorescence have been accounted for in terms of one- and two-photon processes; however, the physical processes arising from the interaction of a single two-level atom with higher photon numbers remain unexplored experimentally. Here we experimentally reveal the multiphoton scattering nature of resonance fluorescence, which intrinsically gives rise to multiphoton entanglement. By accessing quantum fluctuations in the field emitted from a cavity-quantum electrodynamics system, we resolve third- and fourth-order photon scattering events from a single two-level atom. In the three-photon component, the scattered photons are shown to be genuinely energy-time entangled, as verified by a violation of Svetlichny's inequality. As a demonstration of an application, a quantum secret sharing protocol (QSS) is implemented using this entangled photon source. Our study refines the descriptive framework of resonance fluorescence and broadens the scope of its investigation. It also establishes a fundamentally simple route for generating multiphoton entangled states for quantum information processing and quantum metrology.
