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Coexistence of qubit effects

Busch, Paul (orcid.org/0000-0002-2559-9721) and Schmidt, Heinz-Jürgen (2010) Coexistence of qubit effects. Quantum Information Processing. pp. 143-169. ISSN 1573-1332

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Two quantum events, represented by positive operators (effects), are coexistent if they can occur as possible outcomes in a single measurement scheme. Equivalently, the corresponding effects are coexistent if and only if they are contained in the ranges of a single (joint) observable. Here we give several equivalent characterizations of coexistent pairs of qubit effects. We also establish the equivalence between our results and those obtained independently by other authors. Our approach makes explicit use of the Minkowski space geometry inherent in the four-dimensional real vector space of selfadjoint operators in a two-dimensional complex Hilbert space.

Item Type: Article
Copyright, Publisher and Additional Information: © Springer Science+Business Media, LLC 2009. This is an author produced version of a paper published in 'Quantum Information Processing'. Uploaded in accordance with the publisher's self-archiving policy.
Keywords: quantum observables,joint measurability,coexistence,qubit,Electrical and Electronic Engineering,Electronic, Optical and Magnetic Materials,Statistical and Nonlinear Physics,Signal Processing,Modelling and Simulation,Theoretical Computer Science
Institution: The University of York
Academic Units: The University of York > Mathematics (York)
Depositing User: Prof Paul Busch
Date Deposited: 27 Apr 2010 10:04
Last Modified: 31 Jul 2016 00:00
Published Version: http://dx.doi.org/10.1007/s11128-009-0109-x
Status: Published
Refereed: Yes
Related URLs:
URI: http://eprints.whiterose.ac.uk/id/eprint/10761

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