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dc.contributor.authorHiggins, Brendonen_US
dc.contributor.authorDoherty, A.en_US
dc.contributor.authorBartlett, S.en_US
dc.contributor.authorPryde, Geoffen_US
dc.contributor.authorWiseman, Howarden_US
dc.date.accessioned2017-04-24T12:35:05Z
dc.date.available2017-04-24T12:35:05Z
dc.date.issued2011en_US
dc.date.modified2011-10-04T07:17:24Z
dc.identifier.issn10941622en_US
dc.identifier.doi10.1103/PhysRevA.83.052314en_AU
dc.identifier.urihttp://hdl.handle.net/10072/41051
dc.description.abstractWe theoretically investigate schemes to discriminate between two nonorthogonal quantum states given multiple copies. We consider a number of state discrimination schemes as applied to nonorthogonal, mixed states of a qubit. In particular, we examine the difference that local and global optimization of local measurements makes to the probability of obtaining an erroneous result, in the regime of finite numbers of copies N, and in the asymptotic limit as N?8. Five schemes are considered: optimal collective measurements over all copies, locally optimal local measurements in a fixed single-qubit measurement basis, globally optimal fixed local measurements, locally optimal adaptive local measurements, and globally optimal adaptive local measurements. Here an adaptive measurement is one in which the measurement basis can depend on prior measurement results. For each of these measurement schemes we determine the probability of error (for finite N) and the scaling of this error in the asymptotic limit. In the asymptotic limit, it is known analytically (and we verify numerically) that adaptive schemes have no advantage over the optimal fixed local scheme. Here we show moreover that, in this limit, the most naive scheme (locally optimal fixed local measurements) is as good as any noncollective scheme except for states with less than 2% mixture. For finite N, however, the most sophisticated local scheme (globally optimal adaptive local measurements) is better than any other noncollective scheme for any degree of mixture.en_US
dc.description.peerreviewedYesen_US
dc.description.publicationstatusYesen_AU
dc.format.extent567482 bytes
dc.format.mimetypeapplication/pdf
dc.languageEnglishen_US
dc.language.isoen_AU
dc.publisherAmerican Physical Societyen_US
dc.publisher.placeUnited Statesen_US
dc.relation.ispartofstudentpublicationYen_AU
dc.relation.ispartofpagefrom052314-1en_US
dc.relation.ispartofpageto052314-10en_US
dc.relation.ispartofissue5en_US
dc.relation.ispartofjournalPhysical Review Aen_US
dc.relation.ispartofvolume83en_US
dc.rights.retentionYen_AU
dc.subject.fieldofresearchQuantum Information, Computation and Communicationen_US
dc.subject.fieldofresearchQuantum Opticsen_US
dc.subject.fieldofresearchcode020603en_US
dc.subject.fieldofresearchcode020604en_US
dc.titleMultiple-copy state discrimination: Thinking globally, acting locallyen_US
dc.typeJournal articleen_US
dc.type.descriptionC1 - Peer Reviewed (HERDC)en_US
dc.type.codeC - Journal Articlesen_US
gro.facultyGriffith Sciences, School of Natural Sciencesen_US
gro.rights.copyrightCopyright 2011 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.en_AU
gro.date.issued2011
gro.hasfulltextFull Text


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