Why quantum correlations are shocking, Michael Hall

An accessible argument is given for why some correlations between quantum systems boggle our classical intuition. The argument relies on simple properties of joint probabilities, and recovers the standard experimentally-testable Bell inequality in a form that applies equally well to correlations between six-sided dice and between photon polarizations. The observed violation of this inequality implies that the quantities measured on one system cannot have a joint probability distribution that is invariant with respect to the choice of measurement made on a distant system. The possible but extraordinary physical mechanisms underlying this result -- intrinsically incompatible observables, faster-than-light influences and constrained experimental choice -- are briefly discussed. The talk will be at a level suitable for a broad audience.
AIP Theoretical Physics Seminar, May 30, 2024