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dc.contributor.authorHiggins, BL
dc.contributor.authorDoherty, AC
dc.contributor.authorBartlett, SD
dc.contributor.authorPryde, GJ
dc.contributor.authorWiseman, HM
dc.date.accessioned2017-05-03T15:08:00Z
dc.date.available2017-05-03T15:08:00Z
dc.date.issued2011
dc.date.modified2011-10-04T07:17:24Z
dc.identifier.issn1050-2947
dc.identifier.doi10.1103/PhysRevA.83.052314
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.
dc.description.peerreviewedYes
dc.description.publicationstatusYes
dc.format.extent567482 bytes
dc.format.mimetypeapplication/pdf
dc.languageEnglish
dc.language.isoeng
dc.publisherAmerican Physical Society
dc.publisher.placeUnited States
dc.relation.ispartofstudentpublicationY
dc.relation.ispartofpagefrom052314-1
dc.relation.ispartofpageto052314-10
dc.relation.ispartofissue5
dc.relation.ispartofjournalPhysical Review A
dc.relation.ispartofvolume83
dc.rights.retentionY
dc.subject.fieldofresearchMathematical sciences
dc.subject.fieldofresearchPhysical sciences
dc.subject.fieldofresearchQuantum information, computation and communication
dc.subject.fieldofresearchQuantum optics and quantum optomechanics
dc.subject.fieldofresearchChemical sciences
dc.subject.fieldofresearchcode49
dc.subject.fieldofresearchcode51
dc.subject.fieldofresearchcode510803
dc.subject.fieldofresearchcode510804
dc.subject.fieldofresearchcode34
dc.titleMultiple-copy state discrimination: Thinking globally, acting locally
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
gro.facultyGriffith Sciences, School of Natural Sciences
gro.rights.copyright© 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.
gro.date.issued2011
gro.hasfulltextFull Text
gro.griffith.authorWiseman, Howard M.
gro.griffith.authorPryde, Geoff


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