Failure of Local Realism Revealed by Extremely Coarse-Grained Measurements

TL;DR

This paper demonstrates that even with extremely coarse measurements, violations of local realism can be observed, challenging classical intuitions and suggesting that locality may be violated without excluding realism for certain states.

Contribution

It introduces novel scenarios where local realism fails under coarse-grained measurements, even when classical limits are approached.

Findings

Bell's inequality is violated up to the maximum limit with coarse measurements.

Failure of local realism observed even when local states are near classical.

Locality may be violated without excluding realism for specific observables.

Abstract

We show that failure of local realism can be revealed to observers for whom only extremely coarse-grained measurements are available. In our instances, Bell's inequality is violated even up to the maximum limit while both the local measurements and the initial local states under scrutiny approach the classical limit. Furthermore, we can observe failure of local realism when an inequality enforced by non-local realistic theories is satisfied. This suggests that locality alone may be violated while realism cannot be excluded for specific observables and states. Small-scale experimental demonstration of our examples may be possible in the foreseeable future.