Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 54: Posters: Quantum Optics and Photonics IV
Q 54.50: Poster
Thursday, March 12, 2020, 16:30–18:30, Empore Lichthof
Towards long coherence times for a single atom in a standing-wave dipole trap — •Derya Taray1, Tim van Leent1, Robert Garthoff1, Kai Redeker1, Matthias Seubert1, Wei Zhang1, Wenjamin Rosenfeld1,2, and Harald Weinfurter1,2 — 1Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany — 2Max-Planck-Institut für Quantenoptik, Garching, Germany
Long-distance entanglement distribution is the key ingredient in future quantum networks, which will enable distributed quantum computing and quantum communication. To reach long distances, quantum memories with prolonged coherence times are required. Currently we entangle two Rubidium 87 atoms separated by 400 meters via the entanglement swapping protocol [1,2]. Yet, for increasing the separation by at least one order of magnitude the atomic state coherence is the limiting factor, mainly due to position-dependent dephasing in the strongly focused dipole trap.
In this work, we present results towards the implementation of a standing-wave dipole trap, in which the longitudinal field components, causing the dephasing cancel. Two counter-propagating dipole trap beams are focused to 2 micrometer by high-NA objectives, with active phase and directional stabilization of one beam. This should increase the coherence time to several ms, enabling distribution of atom-photon entanglement with a fidelity of 90% over a distance of 100 km.
[1] W. Rosenfeld et al., Phys. Rev. Lett. 119, 010402 (2017)
[2] T. van Leent et al., arXiv: 1909.01006 (2019)