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arXiv · 2511.15413

Bell Inequality Violation with Vacuum-One-Photon Number Superposition States

Zi-Qi Zeng·Jian Wang·Xiu-Bin Liu·Xu-Jie Wang·Li Liu·Hanqing Liu·Haiqiao Ni·Zhichuan Niu·Carlos Antón-Solanas·Bang Wu·Zhiliang Yuan
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Abstract

Entanglement is a central resource in quantum technologies, and the realization of photonic entanglement necessarily relies on interaction with matter. Resonance fluorescence (RF), originating from the coherent interaction between a driving field and a two-level system, plays a pivotal role in quantum optics. Here, we demonstrate a novel route to entanglement generation based on RF from a single quantum dot. Rather than relying on generation of multiphoton states, our approach directly exploits vacuum-one-photon number superposition states created under resonant excitation. By delocalizing this superposition via a beam splitter, we realize time-bin entanglement and observe a clear violation of the Clauser-Horn-Shimony-Holt Bell inequality using Franson-type interferometry. Our scheme removes the need for multiphoton generation, simplifies the experimental requirements, and establishes a scalable pathway toward solid-state entangled photon sources.

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Zi-Qi Zeng, Jian Wang, Xiu-Bin Liu, Xu-Jie Wang, Li Liu, Hanqing Liu, Haiqiao Ni, Zhichuan Niu, Carlos Antón-Solanas, Bang Wu, Zhiliang Yuan. 2025-11-19. Bell Inequality Violation with Vacuum-One-Photon Number Superposition States. https://arxiv.org/abs/2511.15413

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