Experimental test of local observer independence

Massimiliano Proietti, Alexander Pickston, Francesco Graffitti, Peter Barrow, Dmytro Kundys, Cyril Branciard, Martin Ringbauer, Alessandro Fedrizzi

Research output: Contribution to journalArticle

6 Citations (Scopus)
16 Downloads (Pure)

Abstract

The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics the objectivity of observations is not so clear, most markedly exposed in Wigner’s eponymous thought experiment where two observers can experience seemingly different realities. The question whether the observers’ narratives can be reconciled has only recently been made accessible to empirical investigation, through recent no-go theorems that construct an extended Wigner’s friend scenario with four observers. In a state-of-the-art six-photon experiment, we realize this extended Wigner’s friend scenario, experimentally violating the associated Bell-type inequality by five standard deviations. If one holds fast to the assumptions of locality and free choice, this result implies that quantum theory should be interpreted in an observer-dependent way.

Original languageEnglish
Article numbereaaw9832
JournalScience Advances
Volume5
Issue number9
DOIs
Publication statusPublished - 20 Sep 2019

ASJC Scopus subject areas

  • General
  • Physics and Astronomy (miscellaneous)

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    Proietti, M., Pickston, A., Graffitti, F., Barrow, P., Kundys, D., Branciard, C., Ringbauer, M., & Fedrizzi, A. (2019). Experimental test of local observer independence. Science Advances, 5(9), [eaaw9832]. https://doi.org/10.1126/sciadv.aaw9832