Optimal sequential measurements for bipartite state discrimination

Croke, S. , Barnett, S. M. and Weir, G. (2017) Optimal sequential measurements for bipartite state discrimination. Physical Review A: Atomic, Molecular and Optical Physics, 95(5), 052308. (doi: 10.1103/PhysRevA.95.052308)

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State discrimination is a useful test problem with which to clarify the power and limitations of different classes of measurement. We consider the problem of discriminating between given states of a bipartite quantum system via sequential measurement of the subsystems, with classical feed-forward of measurement results. Our aim is to understand when sequential measurements, which are relatively easy to implement experimentally, perform as well, or almost as well, as optimal joint measurements, which are in general more technologically challenging. We construct conditions that the optimal sequential measurement must satisfy, analogous to the well-known Helstrom conditions for minimum error discrimination in the unrestricted case. We give several examples and compare the optimal probability of correctly identifying the state via global versus sequential measurement strategies.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Weir, Mr Graeme and Croke, Dr Sarah and Barnett, Professor Stephen
Authors: Croke, S., Barnett, S. M., and Weir, G.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review A: Atomic, Molecular and Optical Physics
Publisher:American Physical Society
ISSN (Online):1094-1622
Published Online:03 May 2017
Copyright Holders:Copyright © 2017 American Physical Society
First Published:First published in Physical Review A: Atomic, Molecular and Optical Physics 95(5):052308
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
721291Astronomy and physics, theoretical physics and application physics / Quantum Theory. Royal Society Research Professorship.Stephen BarnettThe Royal Society (ROYSOC)RP150122S&E P&A - PHYSICS & ASTRONOMY