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Proceedings Paper

Simple quadrature-based quantum feedback of a solid-state qubit
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Paper Abstract

We analyze the newly proposed quantum feedback loop for a solid-state qubit, based on monitoring the quadrature components of the current from a weakly coupled detector, which continuously measures the qubit. Similar to the earlier proposal of the "Bayesian" feedback, the feedback loop is used to maintain the coherent (Rabi)oscillations in a qubit for an arbitrarily long time; however, this is done in a significantly simpler way, which requires much smaller bandwidth of the control circuitry. The price for simplicity is a less-than-ideal operation: the fidelity is limited to about 95%. The feedback loop operation can be experimentally verified by appearance of a positive in-phase component of the detector current relative to an external oscillating signal used for synchronization. The quadrature-based quantum feedback seems to be within the reach of the present-day technology.

Paper Details

Date Published: 23 May 2005
PDF: 11 pages
Proc. SPIE 5846, Noise and Information in Nanoelectronics, Sensors, and Standards III, (23 May 2005); doi: 10.1117/12.609280
Show Author Affiliations
Alexander N. Korotkov, Univ. of California/Riverside (United States)

Published in SPIE Proceedings Vol. 5846:
Noise and Information in Nanoelectronics, Sensors, and Standards III
Janos A. Bergou; Janusz M. Smulko; Mark I. Dykman; Lijun Wang, Editor(s)

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