Distributing entanglement and single photons through an intra-city, free-space quantum channel

Kevin Resch, Michael Lindenthal, Bibiane Blauensteiner, Hannes Böhm, Alessandro Fedrizzi, Christian Kurtsiefer, Andreas Poppe, Tobias Schmitt-Manderbach, Michael Taraba, Rupert Ursin, Philip Walther, Henning Weier, Harald Weinfurter, Anton Zeilinger

    Publications: Contribution to journalArticlePeer Reviewed

    Abstract

    We have distributed entangled photons directly through the atmosphere to a receiver station 7.8 km away over the city of Vienna, Austria at night. Detection of one photon from our entangled pairs constitutes a triggered single photon source from the sender. With no direct time-stable connection, the two stations found coincidence counts in the detection events by calculating the cross-correlation of locally-recorded time stamps shared over a public internet channel. For this experiment, our quantum channel was maintained for a total of 40 minutes during which time a coincidence lock found approximately 60000 coincident detection events. The polarization correlations in those events yielded a Bell parameter, S=2.27±0.019, which violates the CHSH-Bell inequality by 14 standard deviations. This result is promising for entanglement-based free-space quantum communication in high-density urban areas. It is also encouraging for optical quantum communication between ground stations and satellites since the length of our free-space link exceeds the atmospheric equivalent. © 2005 Optical Society of America
    Original languageEnglish
    Pages (from-to)202-209
    Number of pages8
    JournalOptics Express
    Volume13
    Issue number1
    DOIs
    Publication statusPublished - 10 Jan 2005

    Austrian Fields of Science 2012

    • 103026 Quantum optics

    Keywords

    • KEY DISTRIBUTION
    • OPTICAL COMMUNICATION
    • CRYPTOGRAPHY
    • DAYLIGHT
    • VIOLATION
    • PAIRS
    • TELEPORTATION
    • INEQUALITY
    • EXCHANGE

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