Implementation of generalized quantum measurements: Superadditive quantum coding, accessible information extraction, and classical capacity limit

Journal Article · Sat May 01 04:00:00 EDT 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.69.052329· OSTI ID:20641142

Takeoka, Masahiro; Fujiwara, Mikio; Mizuno, Jun; Sasaki, Masahide ^[1]

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1. National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795 (Japan)

Quantum-information theory predicts that when the transmission resource is doubled in quantum channels, the amount of information transmitted can be increased more than twice by quantum-channel coding technique, whereas the increase is at most twice in classical information theory. This remarkable feature, the superadditive quantum-coding gain, can be implemented by appropriate choices of code words and corresponding quantum decoding which requires a collective quantum measurement. Recently, an experimental demonstration was reported [M. Fujiwara et al., Phys. Rev. Lett. 90, 167906 (2003)]. The purpose of this paper is to describe our experiment in detail. Particularly, a design strategy of quantum-collective decoding in physical quantum circuits is emphasized. We also address the practical implication of the gain on communication performance by introducing the quantum-classical hybrid coding scheme. We show how the superadditive quantum-coding gain, even in a small code length, can boost the communication performance of conventional coding techniques.

• OSTI ID: 20641142
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 69; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CAPACITY
CORRELATIONS
DATA TRANSMISSION
ENERGY LEVELS
GAIN
INFORMATION
INFORMATION THEORY
PERFORMANCE
QUANTUM MECHANICS
SECRECY PROTECTION