Einstein-Podolsky-Rosen steering in symmetrical Gaussian states

Abstract

We have explored quantum Einstein-Podolsky-Rosen steering in symmetric two-mode Gaussian states using Gaussian and non-Gaussian measurements. For Gaussian measurements, we show that steering between the output modes of a symmetric beamsplitter is possible regardless of purity when a threshold input-state quadrature variance compression is achieved. Using the non-Gaussian operators introduced in [1] we show that non-Gaussian measurements can outperform Gaussian measurements for symmetrical states. We also analyze the possibility of asymmetric measurements setups made possible by non-Gaussian measurements and provide examples where such asymmetry is optimal for revealing steering. [1] Ji, SW., Lee, J., Park, J. et al. Quantum steering of Gaussian states via non-Gaussian measurements. Sci Rep 6, 29729 (2016). https://doi.org/10.1038/srep29729