Speaker
Description
Entanglement, especially between bound electrons and photons, forms the basis of most modern quantum technology. The recent observation of entanglement between free electrons and photons in an electron microscope [1,2], could constitute an important step in the development of free-electron quantum optics. While these proof-of-principle experiments open new avenues for integrating quantum metrology concepts into electron microscopes, the current pair-generation rates and degrees of entanglement limit their use in quantum applications.
In this contribution, we explore pathways to achieve improved generation of entangled electron-photon pairs. More specifically, we investigate different potential platforms for the efficient electron-driven generation of photons. This includes the use of multiple photonic waveguides, shown to enable the heralded generation of single photons [3], in which entanglement between an electron’s path and the photon path could be achieved [4,5]. For this specific realisation, we discuss the required experimental conditions and present preliminary results of individual aspects.
Such improved production rates of entangled electron-photon pairs enable the generation of quantum entanglement between electrons (via entanglement swapping) [5], which is a key ingredient for quantum-enhanced sensing in electron microscopy.
[1] J.-W. Henke, H. Jeng, M. Sivis, and C. Ropers, “Observation of quantum entanglement between free electrons and photons,” arXiv:2504.3047 (2025)
[2] Preimesberger et al., “Experimental Verification of Electron-Photon Entanglement,“ arXiv:2504.13163 (2025)
[3] G. Arend, G. Huang, A. Feist, Y. Yang, J.-W. Henke, Z. Qiu, H. Jeng, A. S. Raja, R. Haindl, R. N. Wang, T. J. Kippenberg, and C. Ropers, “Electrons herald non-classical light,” Nat. Phys. 21 (2025)
[4] E. Kazakevich, H. Aharon, and O. Kfir, “Spatial electron-photon entanglement,” Phys. Rev. Res. 6 (2024)
[5] J.-W. Henke, H. Jeng, and C. Ropers, “Probing electron-photon entanglement using a quantum eraser,” Phys. Rev. A 111 (2025)