Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 48: Quanteninformation (Quantenkommunikation)
Q 48.5: Talk
Thursday, March 13, 2008, 17:30–17:45, 1B
Measurement induced decoupling of Gaussian Noise for quantum communication — •Metin Sabuncu1,2, Radim Filip3, Gerd Leuchs2, and Ulrik L. Andersen1,2 — 1Department of Physics, Technical University of Denmark — 2IOIP, Max-Planck Forschungsgruppe, Universität Erlangen-Nürnberg, Germany — 3Department of Optics, Palacky University, Czech Republic
Every communication link is affected by noise. In classical communication the noise does not have a very detrimental influence and can be removed. For quantum communication, however, the effect of this noise becomes much more devastating, normally preventing quantum information processing tasks from being realised. Therefore when performing quantum communication protocols it is crucial to have efficient noise erasing procedures that renders the protocols fault tolerant. We investigate a protocol used in quantum key distribution, where the information is encoded into conjugate continuous variables of a coherent state. We then consider a Gaussian noisy interaction with the environment and show that by performing environmental measurements it is possible to decouple the noise after some suitable measurement induced operations. Using this strategy, the quantum information content of conjugate variables can be ideally recovered independent of the amount of environmental excess noise provided that the state of the environment is fully accessible. We present an experiment in which coherent states are inflicted by Gaussian noise and we present different scenarios how to decouple the noise in the channel via measurement induced operations and compare it to the theory.