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Q: Fachverband Quantenoptik und Photonik
Q 60: Quantum Information II
Q 60.19: Poster
Thursday, March 17, 2022, 16:30–18:30, P
Robust Qubit Encoding for a Single-Atom Quantum Network Link — •Yiru Zhou1,2, Tim van Leent1,2, Florian Fertig1,2, Pooja Malik1,2, Anastasia Reinl1,2, Wei Zhang1,2, and Harald Weinfurter1,2,3 — 1Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany — 2Munich Center for Quantum Science and Technology (MCQST), Munich, Germany — 3Max-Planck-Institut für Quantenoptik, Garching, Germany
The most fundamental task for a quantum network node is to serve as light-matter entanglement interface. For high-quality entanglement distribution over long distances, the quantum memories in such nodes need a quantum storage, i.e, coherence time that is much longer than the travel time of the photons used to distribute the entanglement. Here we represent the improvement of the coherence time of a single-atom quantum memory from 300 µs to more than 5 ms. This is realized via coherently transferring the initial qubit states {|F=1,mF=−1>,|F=1,mF=+1>} to a magnetic-field-insensitive encoding states {F=1,mF=−1>,|F=2,mF=+1>} by a state-selective Raman transfer [1]. Even longer coherence time should become possible by implementing spin-echo and Raman sideband cooling. With these measurement coherence time can increase the reach of our quantum network link from 33 km [2] to hundreds of kilometers.
[1] M. Körber et al., Nat. Photonics 12, 18 (2018)
[2] T. van Leent et al., arXiv: 2111.115526 (2021)