Mainz 2026 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 56: Quantum Optics and Control I
Q 56.4: Talk
Thursday, March 5, 2026, 15:30–15:45, P 3
Observation of entanglement between free electrons and photons — •Jan-Wilke Henke1,2, Hao Jeng1,2, Murat Sivis1,2, and Claus Ropers1,2 — 1Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany — 2University of Göttingen, 4th Physical Institute, Göttingen, Germany
Entanglement is central to most emerging quantum technologies from quantum computation to quantum sensing. Generating entangled quantum states is thus highly relevant for future applications, and has been achieved in various combinations of quantum systems. Here, we demonstrate the quantum entanglement between free electrons and photons [1]. In a quantum eraser-type scheme [2], we use a coherently split electron beam to generate photons of distinct polarisation at a specifically designed nanostructure placed in a transmission electron microscope. Performing electron-photon coincidence measurements in different bases, we reconstruct the joint electron-photon state and show that it violates the Peres-Horodecki entanglement criterion by more than 7 standard deviations. Laying the basis for quantum-enhanced sensing in the electron microscope, the proof of electron-photon entanglement represents a cornerstone of free electron quantum optics. [1] J.-W. Henke et al., arXiv:2504.13047 (2025); [2] J.-W. Henke, H. Jeng & C. Ropers, Phys. Rev. A 111, 012610 (2025)
Keywords: Quantum entanglement; Hybrid quantum systems; Electron-driven photon generation; Electron microscopy