title: Code-division multiple-access multiuser demodulator by using quantum fluctuations.
abstract: We examine the average-case performance of a code-division multiple-access (CDMA) multiuser demodulator in which quantum fluctuations are utilized to demodulate the original message within the context of Bayesian inference. The quantum fluctuations are built into the system as a transverse field in the infinite-range Ising spin glass model. We evaluate the performance measurements by using statistical mechanics. We confirm that the CDMA multiuser modulator using quantum fluctuations achieve roughly the same performance as the conventional CDMA multiuser modulator through thermal fluctuations on average. We also find that the relationship between the quality of the original information retrieval and the amplitude of the transverse field is somehow a "universal feature" in typical probabilistic information processing, viz., in image restoration, error-correcting codes, and CDMA multiuser demodulation.
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-5861, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Otsubo
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan.
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Inoue
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-5861, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Nagata
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-5861, Japan and Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Okada
mesh_terms: D011789:Quantum Theory