Experimentally friendly bounds on non-Gaussian entanglement from second moments

TL;DR

This paper shows that for certain non-Gaussian quantum states, entanglement can be accurately bounded using only second-moment measurements, simplifying the process of entanglement quantification.

Contribution

It introduces bounds on non-Gaussian entanglement based solely on second moments, enabling easier and more practical entanglement estimation.

Findings

Entanglement bounds are derived from second moments.

Estimation error scales with non-Gaussianity.

Covariance matrix suffices for quantification.

Abstract

We demonstrate that the entanglement in a class of two-mode non-Gaussian states obtained by subtracting photons from Gaussian twin beams can be bounded from above and from below by functionals of the second moments only. Knowledge of the covariance matrix thus suffices for an entanglement quantification with appreciable precision. The absolute error in the entanglement estimation scales with the non-Gaussianity of the considered states.