Free-Space Quantum Communication Over 143 km Towards Space

Rupert Ursin
Universität Wien

Free-space quantum communication is becoming a very active filed in quantum optics experiments. This is because it provides the building blocks to bring this new technology into space. In my talk I will present the recent and some not-yet-published proof-of-principle experiments our group was performing on a 143 km long free-space channel between the canary island La Palma and Tenerife. I will talk about our recent achievement of performing quantum teleportation via this channel with active feed-forward in real time. The experiment employed two optical links, quantum and classical, over 143 km free space between the two Canary Islands of La Palma and Tenerife. To achieve this, the experiment had to employ a combination of advanced techniques such as a frequency-uncorrelated polarization-entangled photon pair source, ultra-low-noise single-photon detectors, and entanglement-assisted clock synchronization. The average teleported state fidelity was well beyond the classical limit of 2/3. Furthermore, we confirmed the quality of the quantum teleportation procedure (without feed-forward) by complete quantum process tomography. Our experiment conrms the maturity and applicability of the involved technologies in real-world scenarios, and is a milestone towards future satellite-based quantum teleportation.


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