Gaussian Discriminating Strength

Abstract

We present a quantifier of non-classical correlations for bipartite, multi-mode Gaussian states. It is derived from the Discriminating Strength measure, introduced for finite dimensional systems in A. Farace et al., New. J. Phys. 16, 073010 (2014). As the latter the new measure exploits the Quantum Chernoff Bound to gauge the susceptibility of the composite system with respect to local perturbations induced by unitary gates extracted from a suitable set of allowed transformations (the latter being identified by posing some general requirements). Closed expressions are provided for the case of two-mode Gaussian states obtained by squeezing or by linearly mixing via a beam-splitter a factorized two-mode thermal state. For these density matrices, we study how non-classical correlations are related with the entanglement present in the system and with its total photon number.