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Richard Gill (Leiden University) – “Bell experiments, Bell-denialism, and the quantum Randi challenge “

October 4, 2021 @ 2:00 pm - 3:15 pm
Statistical Seminar: Every Monday at 2:00 pm.
Time: 2:00 pm – 3:15 pm
Date: 4th of October 2021
Place: en visioRichard Gill (Leiden University) – “Bell experiments, Bell-denialism, and the quantum Randi challenge ”

Abstract: John S. Bell’s 1965 theorem, as a piece of pure mathematics, states that the predictions of quantum mechanics cannot be reproduced by theories of a classical physical nature, respecting in particular notions of locality and realism. One can also apply the reasoning behind the theorem to the results of experiments, such as the famous experiment of Alain Aspect in 1981, and go a step further: modulo statistical uncertainty due to the finite amount of data, real laboratory results cannot be reproduced by any mathematical framework compatible with what is now called local realism. It’s not just about quantum mechanics. Aspect’s experiment, however, had a number of (at the time unavoidable) technical weaknesses. His data could be “explained” by classical, local and realistic processes.

At last, four experiments in 2015 (one in Delft) were performed under such stringent laboratory conditions that only “metaphysical” loopholes (such as superdeterminism or retrocausality) remain viable. These “loophole-free” experiments formed the culmination of many years of progress in, step by step, circumventing various “technical” weaknesses of Aspect’s experiments, unavoidable at the time.

I will give a short overview of this progress, focussing on statistical and probabilistic issues, and also speculating on what will happen next. There is still spirited opposition to Bell’s findings, and lively debate in the foundations of physics. Many believe that the problematic reconciliation of relativity and quantum theories is deeply connected to the issues raised by Bell.I will draw a connection with networked computer simulation models. One can forget about physics and see Bell’s theorem as an impossibility theorem in computer science concerning certain tasks to be performed in distributed fashion by networked classical computers. The task should, however, be achievable by quantum computers connected by quantum internet links!