Bell’s Theorem: Setting up the Equipment

Maaneli Derakhshani

Damian Canals‐Frau

Richard David Gill, Gregor Weihs, Anton Zeilinger +1 more

Hess and Philipp recently claimed [(2001) Proc. Natl. Acad. Sci. USA 98, 14224-14227 and 14228-14233] that proofs of Bell's theorem have overlooked the possibility of time dependence in local hidden variables, hence the theorem has not been proven true. Moreover they present what is claimed to be a local realistic model of the EPR correlations. If this is true then Bell's theorem is not just unproven, but false. We refute both claims. First, we explain why time is not an issue in Bell's theorem, and second, we show that their hidden variables model violates Einstein separability. Hess and Philipp have overlooked the freedom of the experimenter to choose settings of a measurement apparatus at will: any setting could be in force during the same time period.

Guido Bacciagaluppi, Ronnie Hermens

In this paper we prove a Bell's theorem in the setting of postselection ('reverse Bell's theorem'). Specifically, we show under which conditions the Bell inequalities can or cannot be violated with classical postselection, and how this differs from the quantum violations. We then propose a variant of existing experiments that discriminates between quantum violations and classical simulations. The proposed experiment can be adapted to test simultaneously the standard and reverse Bell's theorems. In this case, the distinction between these pre- and postselection effects becomes foliation-dependent.

F. J. Duarte

Ramzi Suleiman

Bell's theorem prescribes that no theory of nature that obeys locality and realism can reproduce all the predictions of quantum theory. However, Bell's theorem presupposes that particles that are distanced from each other become spatially disconnected. Yet studies have never experimentally confirmed the possibility of spatial locality between distanced particles. Here, I show that Bell’s theorem cannot forbid an infinite set of local-deterministic relativity theories that violate Lorentz's contraction for distancing bodies. This result in itself cannot guarantee a theory from this set of theories to successfully reproduce the predictions of quantum theory, but until the spatial locality loophole is satisfactorily closed, experiments should be decided the fate of such theories.