Hidden variable models for quantum theory cannot have any local part

TL;DR

This paper demonstrates that quantum correlations cannot be explained by hidden variable models that include any local component, extending Bell's theorem to models with mixed local and non-local parts.

Contribution

It proves the incompatibility of certain quantum correlations with hidden variable models that possess a non-trivial local part, including Leggett's model.

Findings

Quantum correlations cannot be explained by hidden variable models with local parts.

Certain experimentally verifiable quantum correlations contradict models with local components.

The results extend Bell's theorem to more general hidden variable models.

Abstract

It was shown by Bell that no local hidden variable model is compatible with quantum mechanics. If, instead, one permits the hidden variables to be entirely non-local, then any quantum mechanical predictions can be recovered. In this paper, we consider general hidden variable models which can have both local and non-local parts. We then show the existence of (experimentally verifiable) quantum correlations that are incompatible with any hidden variable model having a non-trivial local part, such as the model proposed by Leggett.