Gaussian Discriminating Strength

TL;DR

This paper introduces a new measure for quantifying non-classical correlations in bipartite Gaussian states, based on the Quantum Chernoff Bound, and explores its relation to entanglement and photon number.

Contribution

It extends the Discriminating Strength measure to Gaussian states, providing closed-form expressions and analyzing its relation to entanglement and photon number.

Findings

The measure is explicitly calculated for two-mode Gaussian states.

Non-classical correlations relate to entanglement and total photon number.

The measure offers a new way to quantify quantum correlations in Gaussian systems.

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.