Mainz 2026 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 28: Poster – Quantum Optics
Q 28.24: Poster
Tuesday, March 3, 2026, 17:00–19:00, Philo 2. OG
Engineering of maximally entangled orbital angular momentum states via path identity — •Richard Bernecker1,2, Baghdasar Baghdasaryan3, and Stephan Fritzsche1,2 — 1Institute for Theoretical Physics, Friedrich Schiller University Jena, Fröbelstieg 1, 07743 Jena, Germany — 2Helmholtz Institute Jena, Fröbelstieg 3, 07743 Jena, Germany — 3Institute of Applied Physics, Friedrich Schiller University Jena, Albert-Einstein-Str. 6, 07745 Jena, Germany
Cutting-edge quantum technologies lean on sources of high-dimensional entangled states (HDES) that reliably prepare high-fidelity target states. The idea to overlap photon paths from distinct but indistinguishable sources was recently introduced for the creation of HDES, known as entanglement by path identity. In this regard, the use of orbital angular momentum (OAM) modes is promising, as they offer a high-dimensional and discrete Hilbert space to encode information. While entanglement by path identity with OAM has been verified experimentally, a detailed investigation of how the OAM distribution of photon pairs can be engineered to maximize the entanglement is lacking. We address this gap and identify an optimal dimensionality for maximally entangled states (MESs) when the spatial engineering of the pump beam and the path identity approach are combined. Our theoretical study reveals notable limitations for the fidelity of high-dimensional target states. We also establish the equivalence of entangled biphoton states pumped by a spatially engineered beam and generated via path identity.
Keywords: High-dimensional entanglement; Orbital angular momentum; Photon pairs; Quantum state engineering; Entanglement by path identity