Classical Physics and the Bounds of Quantum Correlations

TL;DR

This paper demonstrates that classical wave models can reproduce quantum correlation bounds, suggesting these bounds are not exclusive to quantum mechanics but also arise in classical wave systems.

Contribution

The study shows classical waves can mimic quantum correlations and reproduce quantum bounds, challenging the notion that these bounds are uniquely quantum.

Findings

Classical microwaves can replicate quantum experiment probabilities.

Quantum bounds are also observed in classical wave systems.

Classical models can produce indistinguishable probability distributions from quantum theory.

Abstract

A unifying principle explaining the numerical bounds of quantum correlations remains elusive despite the efforts devoted to identifying it. Here we show that these bounds are indeed not exclusive to quantum theory: for any abstract correlation scenario with compatible measurements, models based on classical waves produce probability distributions indistinguishable from those of quantum theory and, therefore, share the same bounds. We demonstrate this finding by implementing classical microwaves that propagate along meter-size transmission-line circuits and reproduce the probabilities of three emblematic quantum experiments. Our results show that the "quantum" bounds would also occur in a classical universe without quanta. The implications of this observation are discussed.