Received Papers

Protective measurements and the PBR theorem

Guy Hetzroni and Daniel Rohrlich Forthcoming in Protective Measurement and Quantum Reality: Towards a New Understanding of Quantum Mechanics (CUP, 2015) Protective measurements illustrate how Yakir Aharonov’s fundamental insights into quantum theory yield new experimental paradigms that allow us to test quantum mechanics in ways that were not possible before. As for quantum theory itself, protective measurements demonstrate that a quantum… Read more →

Bell’s theorem without inequalities: on the inception and scope of the GHZ theorem

Olival Freire Jr. and Osvaldo Pessoa Jr. Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” Since its inception, fifty years ago, Bell’s theorem has had a long history not only of experimental tests but also of theoretical developments. Studying pairs of correlated quantum-mechanical particles separated in space, in a composite “entangled” state, Bell (1964) showed that the… Read more →

Weak Values and Quantum Nonlocality

Yakir Aharonov and Eliahu Cohen Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” Entanglement and nonlocality are studied in the framework of pre-/post-selected ensembles with the aid of weak measurements and the Two-State-Vector Formalism.  In addition to the EPR-Bohm experiment, we revisit the Hardy and Cheshire Cat experiments, whose entangled pre- or post-selected states give rise… Read more →

A reasonable thing that just might work

Daniel Rohrlich Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” In 1964, John Bell proved that quantum mechanics is “unreasonable” (to use Einstein’s term):  there are nonlocal bipartite quantum correlations.  But they are not the most nonlocal bipartite correlations consistent with relativistic causality (“no superluminal signalling”):  also maximally nonlocal “superquantum” (or “PR-box”) correlations are consistent with… Read more →

Recollections of John Bell

Michael Nauenberg Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” It is a pleasure to contribute to this anthology some of my recollections of John Bell. I first met him at SLAC, when we were visitors during 1964-65 when he was on leave from CERN, and I was on leave from the Columbia University Physics Department…. Read more →

The Assumptions of Bell’s Proof

Roderich Tumulka Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” While it is widely agreed that Bell’s theorem is an important result in the foundations of quantum physics, there is much disagreement about what exactly Bell’s theorem shows. It is agreed that Bell derived a contradiction with experimental facts from some list of assumptions, thus showing… Read more →

What Retrocausal Explanations Look Like

Ken Wharton Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” While it is generally known that retrocausal models can provide an account of Bell-inequality violations in terms of spacetime-local beables, new models can now explicitly show how this comes about. By analyzing a simple local-beable model that precisely recovers the quantum joint probabilities for measurements on… Read more →

Non-local beables

I would like to begin with Bell’s remark on the possibility that the beables are non-local, which Tim Maudlin quotes. “Of course, we may be obliged to develop theories in which there are no strictly local beables. That possibility will not be considered here[1].” When I read that yesterday I was astounded because it made me realize that ever since encountering Bell’s theorem as… Read more →

Bell on Bohm

Sheldon Goldstein Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” A memorial conference for John Bell, open to the public, was held at Rutgers University around 20 years ago. I gave there a short talk on Bell’s views about David Bohm’s “hidden variables” formulation of quantum mechanics, a version of quantum mechanics often called the de… Read more →

Strengthening Bell’s Theorem: Removing the Hidden-Variable Assumption

Henry P. Stapp Submitted to “Quantum Nonlocality and Reality – 50 Years of Bell’s theorem” The Bell’s theorem proofs are rightly identified as proofs of the incompatibility of “local realism” with the predictions of quantum mechanics. But “local realism” brings in both alien-to-quantum-theory classical concepts and also an “outcome independence” condition whose inclusion nullifies those theorems as possible proofs of… Read more →