**For this frightful Halloween, JPhys+ is focussing on Einstein’s “spooky action at a distance,” non-locality and in particular Bell’s Theorem by highlighting a Journal of Physics A: Mathematical and Theoretical Special Issue on 50 Years of Bell’s Theorem. As highlighted in the preface, the issue contains original research articles and topical reviews, along with more personal perspectives and was guest edited by Nicolas Brunner, Otfried Gühne and Marcus Huber.
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Einstein’s “spooky action at a distance” (*spukhafte Fernwirkung *in German) is one of the most cited statements made by any physicist. Often attributed as Einstein’s description of *non-locality*. Reinhard Werner, in his recent Special Issue paper *Steering, or maybe why Einstein did not go all the way to Bellʼs argument* attempts to bring some clarity of meaning to Einstein’s much cited “spooky action” and the significance of Bell’s Theorem.

Reinhold Bertlmann writes about Bell’s theorem and also the man himself in his witty and engaging personal perspective, *John Bell and the nature of the quantum world*. While Marek Żukowski and Časlav Brukner describe in their paper *Quantum non-locality—it ainʼt necessarily so…* how “Bellʼs theorem, in all its forms, tells us *not* what quantum mechanics *is*, but what quantum mechanics *is not*.”

On behalf of Journal of Physics A I would like to thank all the authors who contributed to work mentioned in this post and the authors and guest editors of the special issue on 50 Years of Bell’s Theorem.

Recent work in this area:

- Determining X-chains in graph states
- An invitation to quantum incompatibility
- Geometric decompositions of Bell polytopes with practical applications

Categories: Journal of Physics A: Mathematical and Theoretical