SAMOP 2023 – scientific programme
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QI: Fachverband Quanteninformation
QI 8: Quantum Communication I (joint session Q/QI)
QI 8.6: Talk
Monday, March 6, 2023, 18:15–18:30, F442
Atom-Photon Entanglement over 101 km Telecom Fiber — •Yiru Zhou1,2, Pooja Malik1,2, Florian Fertig1,2, Matthias Bock3, Tim van Leent1,2, Wei Zhang1,2, Christoph Becher3, and Harald Weinfurter1,2,4 — 1Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany — 2Munich Center for Quantum Science and Technology (MCQST), Munich, Germany — 3Fachrichtung Physik, Universität des Saarlandes, Saarbrücken, Germany — 4Max-Planck-Institut für Quantenoptik, Garching, Germany
The crucial task for future quantum networks is to share entanglement over large distances. For that, quantum systems are required which provide an efficient light-matter interface, long coherence times and the possibility to connect to low-loss quantum channels.
Here we present the distribution of entanglement between an atom and a photon. Spontaneous emission of a photon at 780 nm from a single, trapped Rb-87 atom is employed to obtain entanglement between the polarization of the photon and the respective Zeeman state of the atom. Raman state transfer is used to change the encoding of the atomic qubit in a combination of F=1 & F=2 hyperfine states [1]. The reduced sensitivity to magnetic fields enables one to increase the coherence time to 7 ms. Together with efficient polarization-preserving quantum frequency conversion to telecom wavelengths minimizing the photon loss [2], we demonstrate the distribution of atom-photon entanglement over 101 km telecom fiber with a fidelity ≥70.8%.
[1] M. Körber et al., Nat. Photonics 12, 18 (2018)
[2] T. van Leent et al., Nature 607, 69-73 (2022)