Adaptive Optical Phase Estimation Using Time-Symmetric Quantum Smoothing

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Title Adaptive Optical Phase Estimation Using Time-Symmetric Quantum Smoothing
Author Wheatley, T. A.; Berry, D. W.; Yonezawa, H.; Nakane, D.; Arao, H.; Pope, D. T.; Ralph, T. C.; Wiseman, Howard Mark; Furusawa, A.; Huntington, E. H.
Journal Name Physical Review Letters
Year Published 2010
Place of publication United States
Publisher American Physical Society
Abstract Quantum parameter estimation has many applications, from gravitational wave detection to quantum key distribution. The most commonly used technique for this type of estimation is quantum filtering, using only past observations. We present the first experimental demonstration of quantum smoothing, a time-symmetric technique that uses past and future observations, for quantum parameter estimation. We consider both adaptive and nonadaptive quantum smoothing, and show that both are better than their filtered counterparts. For the problem of estimating a stochastically varying phase shift on a coherent beam, our theory predicts that adaptive quantum smoothing (the best scheme) gives an estimate with a mean-square error up to 2√2 times smaller than nonadaptive filtering (the standard quantum limit). The experimentally measured improvement is 2.24±0.14.
Peer Reviewed Yes
Published Yes
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Copyright Statement Copyright 2010 American Physical Society. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. Please refer to the journal's website for access to the definitive, published version.
Volume 104
Issue Number 9
Page from 093601-1
Page to 093601-4
ISSN 0031-9007
Date Accessioned 2010-05-17
Language en_AU
Research Centre Centre for Quantum Dynamics
Faculty Faculty of Science, Environment, Engineering and Technology
Subject Quantum Optics
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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