Dear all,

Gilles and his former student Paul will continue the series of lectures on local realistic and non-signalling theories already this Wednesday.

At the end of the lecture, we will arrange the time for the final lecture of the series.

Best wishes,

Lídia

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Gilles Brassard and Paul Raymond-Robichaud

Wednesday, 13:45, HIT K52

Local realistic and non-signalling theories. Lecture 2: Mathematical details   Based on https://arxiv.org/abs/1710.01380

This is the second of a series of lectures in which we shall demonstrate the equivalence between local realistic and reversible-dynamics non-signalling theories of physics (which includes unitary quantum theory), Bell’s theorem notwithstanding.

In the first lecture, we saw that it is possible for a local-realistic fantasy world to violate Bell’s inequality even more so than quantum theory. This sufficed to prove that no experimental violations of Bell’s inequality can be considered as proof, or even evidence, that our world cannot be both local and realistic: loophole-free experiments cannot exist by definition since the more experiments agree with the predictions of quantum theory, the more they give evidence that our world can be local and realistic!

In the subsequent lectures, we will start with an easy (yet more substantial than in the first lecture) introduction to what we mean by realistic, local, and non-signalling. Then, we shall delve in the technical definitions of those notions and in the mathematical proof of equivalence between them provided the non-signalling theory exhibits reversible dynamics.