About Wigner Friend’s and Hardy’s paradox in a Bohmian approach: a comment of “Quantum theory cannot consistently describe the use of itself”

Aurélien Drezet (1)

1 NEEL - NOF - Nano-Optique et Forces

This is an analysis of the recently published article 'Quantum theory cannot consistently describe the use of itself' by D. Frauchiger and R. Renner [1]. Here I decipher the paradox and analyze it from the point of view of de Broglie-Bohm hidden variable theory (i.e., Bohmian mechanics). I also analyze the problem from the perspective obtained by the Copenhagen interpretation (i.e., the Bohrian interpretation) and show that both views are self consistent and do not lead to any contradiction with a 'single-world' description of quantum theory. Hardy's paradox; Bohmian mechanics; Lorentz Invariance 1. Hardy's paradox The claim of this article is that the recently published article [1,2] by D. Frauchiger and R. Renner about Wigner's Friends [3] and entanglement is mainly a rephrasing of the beautiful Hardy paradox [4,5] about quantum non-locality without inequality (for a clear and nice derivation see also [6] by S. Goldstein; see also the Greenberger-Horne-Zeilinger (GHZ) paradox [7]). The authors of [1] recognize the importance of Hardy's letter in their own analysis but the argument is written in such a way that the relation is no immediately transparent. My aim is here to clarify this point from the point of view of Bohmian mechanics (i.e., de Broglie Bohm interpretation). During the analysis I will also consider

Mots clés: Nonlocality; observer-independent facts; Wigner Friend's

Domaines: Physique [physics]; Physique Quantique [quant-ph]

Aurélien Drezet. About Wigner Friend’s and Hardy’s paradox in a Bohmian approach: a comment of “Quantum theory cannot consistently describe the use of itself”. International journal of quantum foundations, 2019, 5 (2), pp.80 - 97. ⟨hal-02380166⟩