Generation of a non-zero discord bipartite state with classical second-order interference

TL;DR

This paper demonstrates both theoretically and experimentally that classical second-order interference can generate bipartite states with non-zero quantum discord, providing insights into the nature of quantum correlations beyond entanglement.

Contribution

It is the first to show that classical second-order interference can produce bipartite states with measurable quantum discord, bridging classical optics and quantum information theory.

Findings

Theoretically predicts a bipartite state with discord D=0.311.

Experimentally observes a state with discord D=0.197 +- 0.060.

Highlights the distinction between classical non-classicalities and quantum discord.

Abstract

We report investigation on quantum discord in classical second-order interference. In particular, we theoretically show that a bipartite state with D = 0.311 of discord can be generated via classical second-order interference. We also experimentally verify the theory by obtaining D = 0.197 +- 0.060 of non-zero discord state. Together with the fact that non-classicalities originated from physical constraints and information theoretic perspectives are not equivalent, this result provides an insight to understand the nature of quantum discord.