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Q: Quantenoptik und Photonik

Q 3: Poster Quanteninformation, -kommunikation und Quantencomputer

Q 3.29: Poster

Freitag, 4. März 2005, 11:00–12:30, Poster HU

Tools for long distance quantum communications — •Felix Tiefenbacher — Institut für Experimentalphysik der Universität Wien, Boltzmanngasse 5, A-1090 Wien

To build up a real world quantum network and profit by the properties of quantum communications over long distances new tools and methods need to be developed.

A fiber-based, long distance quantum repeater requires that the fiber length inevitable fluctuations must be compensated and stabilized within the micro meter regime to get a temporal overlap at the Bell-state analyzer’s beamsplitter. There, the two independent photons must be superposed within their coherence time. Thermal fluctuations of the fiber length reduce the overall fidelity of the teleportation. We present an experimental method to determine the maximally acceptable, thermally induced fiber length fluctuations for fiber based quantum teleportation in a quantum repeater configuration.

Furthermore, we present results of a feasibility study for quantum communications in space where we show that quantum communications using a satellite-based source of entangled photons with ground-based receivers is feasible with today’s technology.