Quantum trajectories for the realistic measurement of a solid-state charge qubit

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Title Quantum trajectories for the realistic measurement of a solid-state charge qubit
Author Oxtoby, Neil Paul; Warszawski, Prahlad; Wiseman, Howard Mark; Sun, He-Bi; Polkinghorne, R. E. S.
Journal Name Physical Review B: Condensed Matter and Materials Physics
Year Published 2005
Place of publication Ridge, NY
Publisher American Physical Society
Abstract We present a new model for the continuous measurement of a coupled quantum dot charge qubit. We model the effects of a realistic measurement, namely adding noise to, and filtering, the current through the detector. This is achieved by embedding the detector in an equivalent circuit for measurement. Our aim is to describe the evolution of the qubit state conditioned on the macroscopic output of the external circuit. We achieve this by generalizing a recently developed quantum trajectory theory for realistic photodetectors [P. Warszawski, H. M. Wiseman, and H. Mabuchi, Phys. Rev. A 65, 023802 (2002)] to treat solid-state detectors. This yields stochastic equations whose (numerical) solutions are the "realistic quantum trajectories" of the conditioned qubit state. We derive our general theory in the context of a low transparency quantum point contact. Areas of application for our theory and its relation to previous work are discussed.
Peer Reviewed Yes
Published Yes
Publisher URI http://prola.aps.org/browse/PRB
Alternative URI http://dx.doi.org/10.1103/PhysRevB.71.165317
Copyright Statement Copyright 2005 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 71
Page from 165317.1
Page to 165317.9
ISSN 1098-0121
Date Accessioned 2006-02-23
Language en_AU
Research Centre Centre for Quantum Dynamics
Faculty Faculty of Science
Subject PRE2009-Quantum Optics and Lasers
URI http://hdl.handle.net/10072/4935
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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