Scientific Results

Anomalous values, Fisher information, and contextuality, in generalized quantum measurements

Year: 2020

Authors: Cimini V., Gianani I., Piacentini F., Degiovanni IP., Barbieri M.

Autors Affiliation: ‎Univ Roma Tre, Dipartimento Sci, Via Vasca Navale 84, I-00146 Rome, Italy; Sapienza Univ Roma, Dipartimento Fis, Ple Aldo Moro 5, I-00185 Rome, Italy; INRIM, Str Cacce 91, I-10135 Turin, Italy;‎ CNR, Ist Nazl Ott, Largo Enrico Fermi 6, I-50125 Florence, Italy

Abstract: Postselection following weak measurements has long been investigated for its peculiar manifestation of quantum signatures. In particular, the postselected events can give rise to anomalous values lying outside the spectrum of the measured quantity, and may provide enhanced Fisher information. Furthermore, the Pusey inequality highlights that, for extremely weak measurements, non-contextual models cannot account for the outcome probabilities. It is then interesting to investigate whether these are linked in a unified framework. Here we discuss on the existence of a possible connection in the case of qubits. We show that when performing generic postselected measurements there exist no one-to-one mapping between them, an instance that leads to drawing more involved considerations.

Journal/Review: QUANTUM SCIENCE AND TECHNOLOGY

Volume: 5 (2)      Pages from: 025007  to: 025007

KeyWords: quantum measurements; weak values; contextually; quantum metrology
DOI: 10.1088/2058-9565/ab7988

Citations: 1
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