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Phys. Rev. A 81, 020301(R) (2010) [4 pages]

Replacing quantum feedback with open-loop control and quantum filtering

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Joshua Combes, Howard M. Wiseman, and A. J. Scott
Centre for Quantum Computer Technology, Centre for Quantum Dynamics, Griffith University, Nathan 4111, Australia

Received 16 July 2009; published 4 February 2010

Feedback control protocols can stabilize and enhance the operation of quantum devices, however, unavoidable delays in the feedback loop adversely affect their performance. We introduce a quantum control methodology, combining open-loop control with quantum filtering, which is not constrained by feedback delays. For the problems studied (rapid purification and rapid measurement) we analytically derive lower bounds on the control performance that are comparable with the best corresponding bounds for feedback protocols.

© 2010 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevA.81.020301
DOI:
10.1103/PhysRevA.81.020301
PACS:
03.67.-a, 03.65.Ta, 03.65.Yz, 02.30.Yy