  In recent years the paradigm based on entanglement as the unique measure of
quantum correlations has been challenged by the rise of new correlation
concepts, such as quantum discord, able to reveal quantum correlations that are
present in separable states. It is in general difficult to compute quantum
discord, because it involves a minimization over all possible local
measurements in a bipartition. In the realm of continuous variable (CV)
systems, a Gaussian version of quantum discord has been put forward upon
restricting to Gaussian measurements. It is natural to ask whether non-Gaussian
measurements can lead to a stronger minimization than Gaussian ones. Here we
focus on two relevant classes of two-mode Gaussian states: squeezed thermal
states (STS) and mixed thermal states (MTS), and allow for a range of
experimentally feasible non-Gaussian measurements, comparing the results with
the case of Gaussian measurements. We provide evidence that Gaussian
measurements are optimal for Gaussian states.
