title: Experimental demonstration of adaptive quantum state estimation.
abstract: The first experimental demonstration of an adaptive quantum state estimation (AQSE) is reported. The strong consistency and asymptotic efficiency of AQSE have been mathematically proven [A. Fujiwara, J. Phys. A 39, 12489 (2006)]. In this Letter, the angle of linear polarization of single photons, the phase parameter between the right and the left circularly polarization, is estimated using AQSE, and the strong consistency and asymptotic efficiency are experimentally verified. AQSE will provide a general useful method in both quantum information processing and metrology.
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Kita-ku, Sapporo 001-0020, Japan and The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Okamoto
authors.forename: Minako
authors.initials: M
authors.lastname: Iefuji
authors.forename: Satoshi
authors.initials: S
authors.lastname: Oyama
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamagata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imai
authors.forename: Akio
authors.initials: A
authors.lastname: Fujiwara
authors.forename: Shigeki
authors.initials: S
authors.lastname: Takeuchi