Violation of Bell's inequality for phase singular beams

TL;DR

This paper demonstrates that classical optical beams with phase singularities can violate Bell's inequality using the Wigner distribution function, revealing a new form of Bell's inequality applicable to both classical and quantum systems.

Contribution

It introduces a novel experimental verification of Bell's inequality violation in classical beams with phase singularities using the Wigner distribution function.

Findings

Classical phase singular beams violate Bell's inequality.

The violation is demonstrated using the Wigner distribution function.

A new form of Bell's inequality applicable to classical and quantum systems is established.

Abstract

We have considered optical beams with phase singularity and experimentally verified that these beams, although being classical, have properties of two mode entanglement in quantum states. We have observed the violation of Bell's inequality for continuous variables using the Wigner distribution function (WDF) proposed by Chowdhury et al. [Phys. Rev. A \textbf{88}, 013830 (2013)]. Our experiment establishes a new form of Bell's inequality in terms of the WDF which can be used for classical as well as quantum systems.