Andrea Di Biagio
IQOQI Vienna Bell, Wigner, causal reasoning, and interpretations
Bell’s theorem and Bell inequality violations are one of the most iconic results in quantum physics. While certainly further from experimental realisation, experiments involving quantum control of observers—the so-called Extended Wigner’s friend scenarios—pose an even stronger challenge to our understanding of quantum theory. In this talk, after a review of the implications of Bell and Local Friendliness no-go theorems on the interpretations of quantum mechanics, I will present a recent result about the failure of causal reasoning in dealing with the predictions of quantum mechanics in extended Wigner’s friend scenarios: not just classical causal reasoning, but causal reasoning using generalised probabilistic theories fails to faithfully account for the predictions of QM.