Consequences of the single-pair measurement of the Bell parameter

TL;DR

This paper discusses the implications of a novel single-pair measurement of the Bell parameter, which could influence interpretations of quantum mechanics and foundational debates.

Contribution

It analyzes how a recent experiment estimating the Bell-CHSH parameter from a single entangled pair impacts quantum foundations and interpretation debates.

Findings

First experimental estimation of Bell-CHSH parameter from a single pair

Potential to address loopholes and interpretative issues in Bell tests

Implications for quantum mechanics foundations and interpretations

Abstract

Bell inequalities represent a milestone for contemporary Physics, both for quantum foundations investigation and technological applications (e.g., quantum communication and entanglement certification). Although loophole-free tests have been recently performed, a strong debate is still ongoing on the actual meaning of Bell inequality tests, for example on the possible additional hypotheses (end eventual loopholes) to be included in Bell's theorem, as well as on the implications for certain interpretations of quantum mechanics. A recent work [S. Virz\`i et al., Quantum Sci. Technol. 9, 045027 (2024)] challenges some of the statements appeared in this debate, achieving for the first time an experimental estimation of the entire Bell-CHSH parameter from a single entangled pair thanks to a weak-interaction-based measurement approach. Here we analyse the implications of this result for quantum mechanics foundations investigation, illustrating how it can tackle some of the aforementioned interpretations of Bell inequality tests and, more in general, of quantum mechanics itself.