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QI: Fachverband Quanteninformation
QI 18: Quantum Technologies: Trapped Ions (joint session Q/QI)
QI 18.4: Talk
Wednesday, March 8, 2023, 11:45–12:00, F342
Quantum repeater node with two 40Ca+ ions — •Max Bergerhoff, Omar Elshehy, Stephan Kucera, Matthias Kreis, and Jürgen Eschner — Universität des Saarlandes, Experimentalphysik, 66123 Saarbrücken
The quantum repeater cell according to [1] is a fundamental building block for large distance quantum networks. It serves for overcoming the exponential scaling of fiber transmission, by the division of a transmission fiber in two asynchronously driven segments and the use of quantum memories. Recent realizations with single atoms [2] in a cavity and ions in a large cavity [3] already demonstrate the advantage of this protocol. Here we report on the implementation of a free-space quantum repeater cell with two 40Ca+ ions in the same trap that act as memories.
We demonstrate ion-photon entanglement according to [4] by controlled emission of single photons from the individually addressed ions. The entanglement is swapped onto the photons via the Mølmer-Sørensen gate [5]. We discuss the rate scaling due to the asynchronous sequence and the fidelity of the final photon-photon state.
[1] D. Luong et al., Appl. Phys. B 122, 96 (2016)
[2] S. Langenfeld et al., Phys. Rev. Lett. 126, 30506 (2021)
[3] V. Krutyanskiy et al. arXiv preprint arXiv:2210.05418 (2022)
[4] M. Bock et al., Nat. Commun. 9, 1998 (2018)
[5] K. Mølmer and A. Sørensen, Phys. Rev. Lett 82, 1835-8 (1999)