Feedback-stabilization of an arbitrary pure state of a two-level atom

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Title Feedback-stabilization of an arbitrary pure state of a two-level atom
Author Wang, Jin; Wiseman, Howard Mark
Journal Name Physical Review A: Atomic, Molecular and Optical Physics
Editor Bernd Crasemann
Year Published 2001
Place of publication USA
Publisher American Physical Society
Abstract Unit-efficiency homodyne detection of the resonance fluorescence of a two-level atom collapses the quantum state of the atom to a stochastically moving point on the Bloch sphere. Recently, Hofmann, Mahler, and Hess [Phys. Rev. A 57, 4877 (1998)] showed that by making part of the coherent driving proportional to the homodyne photocurrent one can stabilize the state to any point on the bottom-half of the sphere. Here we reanalyze their proposal using the technique of stochastic master equations, allowing their results to be generalized in two ways. First, we show that any point on the upper- or lower-half, but not the equator, of the sphere may be stabilized. Second, we consider nonunit-efficiency detection, and quantify the effectiveness of the feedback by calculating the maximal purity obtainable in any particular direction in Bloch space.
Peer Reviewed Yes
Published Yes
Publisher URI http://prola.aps.org/browse/PRA
Alternative URI http://dx.doi.org/10.1103/PhysRevA.64.063810
Copyright Statement Copyright 2001 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 64
Issue Number 6
Page from 063810.1
Page to 063810.9
ISSN 1050-2947
Date Accessioned 2002-04-15
Date Available 2009-12-01T05:29:44Z
Language en_AU
Research Centre Centre for Quantum Dynamics
Faculty Faculty of Science
Subject PRE2009-Theoretical Physics
URI http://hdl.handle.net/10072/3761
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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