Bonn 2025 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 2: Quantum Networks, Repeaters, and QKD I (joint session Q/QI)
Q 2.4: Vortrag
Montag, 10. März 2025, 12:00–12:15, AP-HS
Quantum repeater segment with trapped 40Ca+ ions — •Max Bergerhoff, Pascal Baumgart, and Jürgen Eschner — Universität des Saarlandes, Experimentalphysik, 66123 Saarbrücken, Germany
The quantum repeater (QR) segment, as part of a QR link [1], is a fundamental building block for the realization of large-distance quantum networks. By dividing a transmission link into segments and cells it is possible to overcome the exponential loss of direct transmission. Experiments that create atom-atom entanglement with single atoms [2] or single ions in cavities [3] have demonstrated the potential of the atom/ion platform for a QR segment.
We report the implementation of a QR segment with free-space coupled photons from two 40Ca+ ions in the same Paul trap as memories. Atom-photon entanglement is produced [4] by controlled emission of single photons from the ions via excitation with nanosecond laser pulses and separate single-mode fiber coupling.
Atom-atom entanglement is then generated by a photonic Bell-state measurement.
A full QR link will combine the QR segment with the already demonstrated QR cell [5]; this will require a new ion trap setup with integrated sub-mm cavity, currently under construction.
[1] P. van Loock et al., Adv. Quantum Technol., 3: 1900141 (2020)
[2] T. van Leent et. al., Nature 607, 69-73 (2022)
[3] V. Krutyanskiy et al., Phys. Rev. Lett. 130, 050803 (2023)
[4] M. Bock et al., Nat. Commun. 9, 1998 (2018)
[5] M. Bergerhoff et al., Phys. Rev. A 110, 032603 (2024)
Keywords: Quantum repeater segment; Trapped ion; Atom-photon entanglemet; Atom-atom entanglemet