Model for monitoring of a charge qubit using a radio-frequency quantum point contact including experimental imperfections

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Title Model for monitoring of a charge qubit using a radio-frequency quantum point contact including experimental imperfections
Author Oxtoby, Neil Paul; Gambetta, Jay; Wiseman, Howard Mark
Journal Name Physical Review B (Condensed Matter and Materials Physics)
Editor P D Adams
Year Published 2008
Place of publication United States
Publisher American Physical Society
Abstract The extension of quantum trajectory theory to incorporate realistic imperfections in the measurement of solid-state qubits is important for quantum computation, particularly for the purposes of state preparation and error correction as well as for readout of computations. Previously this has been achieved for low-frequency (dc) weak measurements. In this paper we extend realistic quantum trajectory theory to include radio frequency (rf) weak measurements where a low-transparency quantum point contact (QPC), coupled to a charge qubit, is used to damp a classical oscillator circuit. The resulting realistic quantum trajectory equation must be solved numerically. We present an analytical result for the limit of large dissipation within the oscillator (relative to the QPC), where the oscillator slaves to the qubit. The rf+dc mode of operation is considered. Here the QPC is biased (dc) as well as subjected to a small-amplitude sinusoidal carrier signal (rf). The rf+dc QPC is shown to be a low-efficiency charge-qubit detector, which may nevertheless be higher than the dc-QPC (which is subject to 1/f noise).
Peer Reviewed Yes
Published Yes
Publisher URI http://prb.aps.org/
Alternative URI http://dx.doi.org/10.1103/PhysRevB.77.125304
Copyright Statement Copyright 2008 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 77
Page from 125304 -1
Page to 125304 -11
ISSN 1098-0121
Date Accessioned 2008-11-28
Date Available 2009-12-21T03:11:57Z
Language en_AU
Research Centre Centre for Quantum Dynamics
Faculty Faculty of Science, Environment, Engineering and Technology
Subject PRE2009-Theoretical Physics
URI http://hdl.handle.net/10072/22531
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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