Tripartite non-separability in classical optics

TL;DR

This paper demonstrates the experimental creation of a tripartite non-separable state in classical optics, resembling quantum GHZ states, which can violate Mermin's inequality and has potential applications in advanced optical technologies.

Contribution

It reports the first experimental realization of a tripartite non-separable classical optical state analogous to quantum entanglement.

Findings

Violates Mermin's inequality with classical light

Creates GHZ-like states using path, polarization, and transverse modes

Opens new avenues for classical optical applications inspired by quantum protocols

Abstract

It is possible to prepare classical optical beams which cannot be characterized by a tensor product of vectors describing each of their degrees of freedom. Here we report the experimental creation of such a non-separable, tripartite GHZ-like state of path, polarization and transverse modes of a classical laser beam. We use a Mach-Zehnder interferometer with an additional mirror and other optical elements to perform measurements that violate Mermin's inequality. This demonstration of a classical optical analogue of tripartite entanglement paves the path to novel optical applications inspired by multipartite quantum information protocols.