Experimentally faking the violation of Bell's inequalities

TL;DR

This paper demonstrates that classical light can mimic Bell inequality violations, emphasizing the importance of strict locality and efficiency conditions in experiments, especially for security applications.

Contribution

It reveals how classical light can fake Bell violations under typical experimental setups, challenging assumptions about non-classicality proofs.

Findings

Classical light can produce Bell inequality violations in standard experiments.

Strict locality and efficiency are crucial for valid Bell tests.

Implications for security protocols relying on Bell violations.

Abstract

Entanglement witnesses such as Bell inequalities are frequently used to prove the non-classicality of a light source and its suitability for further tasks. By demonstrating Bell inequality violations using classical light in common experimental arrangements, we highlight why strict locality and efficiency conditions are not optional, particularly in security-related scenarios.