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PHYSICS NEWS UPDATE The American Institute of Physics Bulletin of Physics News Number 815 March 16, 2007 by Phillip F. Schewe, Ben Stein www.aip.org/pnu [...] WIRELESS TRANSMISSION OF QUANTUM CODE over a distance of 144 kilometers (89 miles) between two Canary Islands has been demonstrated by a team of researchers in Europe. At the APS March Meeting, Anton Zeilinger of the University of Vienna ([EMAIL PROTECTED]) described how he and his colleagues transmitted single photons from an astronomical observatory in La Palma Island to another one in Tenerife. The transmitted photons' polarization states (representing 0s and 1s) formed the basis of a "quantum key," a stream of information that could be used to decipher a longer encrypted message. The researchers used single photons because they are more secure than groups of photons, from which an eavesdropper could pluck information about the key. To detect potential eavesdroppers even better, the researchers entangled the outgoing particles of light with photons kept at the transmitting station. They used astronomy stations because their telescopes are sensitive enough to detect individual photons. The data transmission rate was low, only 178 photons in 75 seconds, but the photons are able to travel longer distances in free space (potentially thousands of kilometers or more) than they are in fiber optic cables (100 km) before they become undetectable. In a proposed experiment to be coordinated by the European Space Agency (ESA, which operates the Tenerife telescope and which participated in the Canary Islands experiment) the International Space Station can transmit entangled key to two earthbound stations separated by distances ten times greater or more. (For a preprint, see Ursin et al., quant-ph/0607182) *********** PHYSICS NEWS UPDATE is a digest of physics news items arising from physics meetings, physics journals, newspapers and magazines, and other news sources. It is provided free of charge as a way of broadly disseminating information about physics and physicists. For that reason, you are free to post it, if you like, where others can read it, providing only that you credit AIP. Physics News Update appears approximately once a week. AUTO-SUBSCRIPTION OR DELETION: By using the expression "subscribe physnews" in your e-mail message, you will have automatically added the address from which your message was sent to the distribution list for Physics News Update. If you use the "signoff physnews" expression in your e-mail message, the address in your message header will be deleted from the distribution list. Please send your message to: [EMAIL PROTECTED] (Leave the "Subject:" line blank.) -- Sean McGrath [EMAIL PROTECTED] --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]