Target Detection with Asymmetric Gaussian Classical Correlation

We study the characteristics of two-mode classical correlation in Gaussian regime, which is produced by impinging a thermal state into a beam splitter. It is explicitly investigated how a measurement on one mode affects the other. The result enables the distinction between classical and quantum correlations. Then, we show how classically correlated states are advantageous in target detection, specifically for an asymmetric classical correlation with different mean photon numbers in the signal and idler modes. Under on-off detection, the classically correlated states significantly outperform quantum correlated states as the environmental thermal mean photon number increases. Furthermore, we demonstrate the advantage of local Gaussian operations in the target detection.