Mainz 2026 – scientific programme

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A: Fachverband Atomphysik

A 11: Atomic Systems in External Fields I

A 11.5: Talk

Tuesday, March 3, 2026, 12:15–12:30, N 2

Extracting pairs of time-bin entangled photons from resonance fluorescence — •xinxin hu, gabriele maron, luke masters, arno rauschenbeutel, and jürgen volz — Department of Physics, Humboldt Universität zu Berlin, 10099 Berlin, Germany

Photon-photon entanglement and photon antibunching are fundamental manifestations of the quantum nature of optical light fields, but are typically regarded as distinct phenomena. Here, we experimentally demonstrate that pairs of narrow-band time-bin entangled photons can be naturally extracted from resonance fluorescence. We split the collected fluorescence of a single trapped atom on a 50:50 beamsplitter, resulting in strong temporal correlations between photons at the beamsplitter outputs. A time-bin coincidence between the two output modes then projects their state onto a maximally entangled Bell state. This entanglement is evidenced by violating the CHSH-Bell inequality as well as by reconstructing the density matrix of the photon pair. Importantly, we show that the entanglement persists both for weak and strong excitation of the emitter. Our results establish resonance fluorescence as an efficient source of time-bin entangled photon pairs, i.e., a practical and scalable resource for quantum communication and photonic quantum technologies.

Keywords: Resonance fluorescence; Time-bin entanglement; Photon antibunching; CHSH-Bell inequality violation