Are Bell-tests only about local incompatibility?

TL;DR

This paper argues that Bell-test violations are primarily due to non-local incompatibility of joint measurements, emphasizing non-locality as essential for interpreting quantum measurement outcomes.

Contribution

It clarifies that non-local incompatibility, not local incompatibility, is key to Bell-test violations, challenging the view that non-locality is unnecessary in quantum physics.

Findings

Bell-test violations stem from non-local incompatibility.

Non-locality is essential for interpreting joint quantum measurements.

Local incompatibility alone does not explain Bell-CHSH violations.

Abstract

The view exists that Bell-tests would only be about local incompatibility of quantum observables and that quantum non-locality would be an unnecessary concept in physics. In this note, we emphasize that it is not incompatibility at the local level that is important for the violation of Bell-CHSH inequality, but incompatibility at the non-local level of the joint measurements. Hence, non-locality remains a necessary concept to properly interpret the outcomes of certain joint quantum measurements.