Experimental realization of robust weak measurements

Enrico Rebufello, Fabrizio Piacentini, Alessio Avella, M. A. De Souza, Marco Gramegna, Jan Dziewior, Eliahu Cohen, Lev Vaidman, Ivo P. Degiovanni, Marco Genovese

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Despite being very influential on both foundations and applications of quantum mechanics, weak values are still somewhat controversial. Although there are some indications that weak values are physical properties of a single quantum system, the common way weak values are presented is statistical: it is commonly believed that for measuring weak values one has to perform many weak measurements over a large ensemble of pre- and postselected particles. Other debates surround the anomalous nature of weak value and even their quantumness. To address these issues, we present some preliminary data showing that anomalous weak values can be measured using just a single detection, i.e. with no statistics. In our experiment, a single click of a detector indicates the weak value as a single photon property, which moreover lies well beyond the range of eigenvelues of the measured operator. Importantly, the uncertainty with which the weak values is measured is smaller than the difference between the weak value and the closet eigenvalue. This is the first experimental realization of robust weak measurements.

Original languageEnglish
Title of host publicationOptical, Opto-Atomic, and Entanglement-Enhanced Precision Metrology II
EditorsSelim M. Shahriar, Jacob Scheuer
ISBN (Electronic)9781510633551
StatePublished - 2020
EventOptical, Opto-Atomic, and Entanglement-Enhanced Precision Metrology II 2020 - San Francisco, United States
Duration: 1 Feb 20206 Feb 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical, Opto-Atomic, and Entanglement-Enhanced Precision Metrology II 2020
Country/TerritoryUnited States
CitySan Francisco

Bibliographical note

Funding Information:
The authors acknowledge the European Union’s Horizon 2020 and the EMPIR Participating States in the context of the projects 17FUN01 “BeCOMe” and 17FUN06 “SIQUST”, the European Union’s Horizon 2020 project “Pathos”, the U.S.-Israel Binational Science Foundation Grant No. 735/18 for financial support and JD acknowledges support from the PhD program IMPRS-QST.

Publisher Copyright:
© 2020 SPIE.


  • protective measurement
  • quantum metrology
  • weak measurement
  • weak value


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