Squashing Models for Optical Measurements in Quantum Communication
- 25 August 2008
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 101 (9), 093601
- https://doi.org/10.1103/physrevlett.101.093601
Abstract
Measurements with photodetectors are naturally described in the infinite dimensional Fock space of one or several modes. For some measurements, a model has been postulated which describes the full measurement as a composition of a mapping (squashing) of the signal into a small dimensional Hilbert space followed by a specified target measurement. We present a formalism to investigate whether a given measurement pair of full and target measurements can be connected by a squashing model. We show that a measurement used in the Bennett-Brassard 1984 (BB84) protocol does allow a squashing description, although the corresponding six-state protocol measurement does not. As a result, security proofs for the BB84 protocol can be based on the assumption that the eavesdropper forwards at most one photon, while the same does not hold for the six-state protocol.Keywords
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This publication has 10 references indexed in Scilit:
- Symmetry of large physical systems implies independence of subsystemsNature Physics, 2007
- Quantum key distribution with entangled photon sourcesPhysical Review A, 2007
- Optimum quantum error recovery using semidefinite programmingPhysical Review A, 2007
- Geometry of Quantum StatesPublished by Cambridge University Press (CUP) ,2006
- Iterative Optimization of Quantum Error Correcting CodesPhysical Review Letters, 2005
- Security against individual attacks for realistic quantum key distributionPhysical Review A, 2000
- Incoherent and coherent eavesdropping in the six-state protocol of quantum cryptographyPhysical Review A, 1999
- Estimates for practical quantum cryptographyPhysical Review A, 1999
- Optimal Eavesdropping in Quantum Cryptography with Six StatesPhysical Review Letters, 1998
- Linear transformations which preserve trace and positive semidefiniteness of operatorsReports on Mathematical Physics, 1972