A1 Refereed original research article in a scientific journal

Quantum instruments: II. Measurement theory




AuthorsPellonpaa JP

PublisherIOP PUBLISHING LTD

Publication year2013

JournalJournal of Physics A: Mathematical and Theoretical

Journal name in sourceJOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL

Journal acronymJ PHYS A-MATH THEOR

Article numberARTN 025303

Number in series2

Volume46

Issue2

Number of pages15

ISSN1751-8113

DOIhttps://doi.org/10.1088/1751-8113/46/2/025303


Abstract
For any quantum observable (positive operator valued measure (POVM)), we show that its compatible quantum instruments can be identified with certain channels and can be seen as combinations of Luders operations and channels. We prove that a POVM is rank-1 exactly when its compatible instruments are nuclear and their associate channels are entanglement-breaking. Any instrument can be maximally refined into a rank-1 instrument. We present a characterization for (minimal) pure realizations of instruments and characterize completely the minimal pure measurement models of POVMs. The standard model of quantum measurement theory is generalized for arbitrary observables. Finally, we study post measurement states.



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