Quantum key distribution using quantum-correlated photon sources |
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Authors: | PJ Edwards GH Pollard WN Cheung |
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Institution: | (1) Advanced Telecommunications and Quantum Electronics Research Centre, University of Canberra, Canberra ACT 2601, Australia, AU |
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Abstract: | Quantum key exchanges using weak coherent (Poissonian) single-photon sources are open to attack by a variety of eavesdropping
techniques. Quantum-correlated photon sources provide a means of flagging potentially insecure multiple-photon emissions and
thus extending the secure quantum key channel capacity and the secure key distribution range. We present indicative photon-counting
statistics for a fully correlated Poissonian multibeam photon source in which the transmitted beam is conditioned by photon
number measurements on the remaining beams with non-ideal multiphoton counters. We show that significant rejection of insecure
photon pulses from a twin-beam source cannot be obtained with a detector having a realistic quantum efficiency. However quantum-correlated
(quadruplet or octuplet) multiplet photon sources conditioned by high efficiency multiphoton counters could provide large
improvements in the secure channel capacity and the secure distribution range of high loss systems such as those using the
low earth orbit satellite links proposed for global quantum key distribution.
Received 14 July and Received in final form 20 November 2001 |
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Keywords: | PACS 03 67 Dd Quantum cryptography – 02 50 Fz Stochastic analysis – 42 50 Lc Quantum fluctuations quantum noise and quantum jumps |
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