Optical nonclassicality test based on third-order intensity correlations

Abstract

We develop a nonclassicality criterion for the interference of three delayed, but otherwise identical, light fields in a three-mode Bell interferometer. We do so by comparing the prediction of quantum mechanics with those of a classical framework in which independent sources emit electric fields with random phases. In particular, we evaluate third-order correlations among output intensities as a function of the delays, and show how the presence of a correlation revival for small delays cannot be explained by the classical model of light. The observation of a revival is thus a nonclassicality signature, which can be achieved only by sources with a photon-number statistics that is highly sub-Poissonian. Our analysis provides strong evidence for the nonclassicality of the experiment discussed by Menssen et al., [A. J. Menssen et al., Phys. Rev. Lett. 118, 153603 (2017)], and shows how a collective "triad" phase affects the interference of any three or more light fields, irrespective of their quantum or classical character.

Signatures of many-particle interference

“…For instance, a more profound extension of the method that considers three-point correlations was explored in [98]. Finally, the approach based on the C-dataset is closely related to those that use the g (2) and g (3) functions [99,100].…”