Noise and Bell's inequality

Understand

From the beginning of quantum mechanics, there has been a discussion about the concept of reality, as exemplified by the EPR paradox.

• To many, the idea of the paradox and the possibility of local hidden variables was dismissed by the Bell inequality.
• Yet, there remains considerable evidence that this inequality can be violated even by classical systems, so that experiments showing quantum behavior and the violation of the inequality must be questioned.
• Here, we demonstrate that classical optical polarization experiments based upon noise in the system can be shown to violate the Bell inequality.