Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 48: Quanteninformation (Quantenkommunikation)
Q 48.9: Talk
Thursday, March 13, 2008, 18:30–18:45, 1B
Distillation of entangled state after a fading channel — •Ruifang Dong1, Mikael Lassen2, Christoph Marquardt1, Radim Filip1, Ulrik L. Andersen2, and Gerd Leuchs1 — 1Institute for Optics, Information and Photonics,Max-Planck Researchgroup, University Erlangen-Nuernberg, Guenther-Scharowsky-Str. 1, 91058, Erlangen,Germany — 2Department of Physics, Technical University of Denmark, Building 309, 2800 Lyngby, Denmark
We report on the experimental distillation of a continuous variable polarization entangled state which is affected by a fading channel. We produce a polarization entangled state by mixing two fiber-based polarization squeezing states at a beam splitter [1]. After the beam splitter, one part of the entangled beams is subject to a fading channel. Such channel may exhibit any kind of random distribution of the attenuation. In the experiment, to simulate the fading channel and implement the distillation, we insert a variable optical attenuator into one of the entangled beams and tap off a small portion of the attenuated beam for post selection [2], the joint measurement on the corrupted entangled beams is also made for verification. Then by setting various different attenuation levels, we achieve a series of data from tap measurements and verification measurements which are collected by A/D card into computer. Later, all the measured data can be mixed in the computer with certain distribution form and a destroyed entangled state after a certain fading channel is simulated. Based on such procedure, the distillation can be succeeded and a recovery of the original entangled state is obtained with an accessible success probability.