We experimentally determine the quantum discord present in two-mode squeezed vacuum generated by a four-wave mixing process in hot rubidium vapor. The frequency spectra of the discord, as well as the quantum and classical mutual information are also measured. In addition, the effects of symmetric attenuation introduced into both modes of the squeezed vacuum on the discord, the quantum mutual information and the classical correlations are examined experimentally. Finally, we show that due to the multi-spatial-mode nature of the four-wave mixing process, the quantum discord may exhibit sub- or superadditivity depending on which spatial channels are selected.
@article{arxiv.1209.6079,
title = {Experimental characterization of Gaussian quantum discord generated by four-wave mixing},
author = {Ulrich Vogl and Ryan T. Glasser and Quentin Glorieux and Jeremy B. Clark and Neil Corzo-Trejo and Paul D. Lett},
journal= {arXiv preprint arXiv:1209.6079},
year = {2020}
}