On Bell, Suarez-Scarani, and Leggett experiments: Reply to a comment, and proposal for a new experiment

TL;DR

This paper clarifies the implications of specific Bell-type experiments on hidden variable models, showing that certain experiments refute classes of nonlocal realistic theories and proposing a new experiment to further test quantum nonlocality.

Contribution

It demonstrates that the before-before experiment refutes deterministic nonlocal hidden variable models and that Leggett-type inequality violations challenge models with biased local randomness, clarifying interpretations of prior experiments.

Findings

Before-before experiment refutes deterministic nonlocal hidden variables

Violation of Leggett inequalities challenges biased local randomness models

Proposes a new experiment to test nonlocal realism

Abstract

It is shown that the before-before (or Suarez-Scarani) experiment refutes hidden variable models with a deterministic ("realistic") nonlocal part, and the experimental violation of Leggett-type inequalities models with a random nonlocal part and a biased random local one. Therefore the claim that Groeblacher et al. present "an experimental test of nonlocal realism" [Nature, 446, 871-875 (2007)] is misleading, and Marek Zukowski's comment [arXiv:0809.0072v1] misses the point. A new experiment is proposed.