Superior Resilience of Non-Gaussian Entanglement against Local Gaussian Noises

Entanglement distribution task encounters a problem of how the initial entangled state should be prepared in order to remain entangled the longest possible time when subjected to local noises. In the realm of continuous-variable states and local Gaussian channels it is tempting to assume that the optimal initial state with the most robust entanglement is Gaussian too; however, this is not the case. Here we prove that specific non-Gaussian two-mode states remain entangled under the effect of deterministic local attenuation or amplification (Gaussian channels with the attenuation factor/power gain k i and the noise parameter m i for modes i = 1, 2) whenever k1 mu(2)(2) + k(2) mu(2)(1) < 1/4 (k(1) + k(2))(1 + k(1) k(2)), which is a strictly larger area of parameters as compared to where Gaussian entanglement is able to tolerate noise. These results shift the Gaussian world paradigm in quantum information science (within which solutions to optimization problems involving Gaussian channels are supposed to be attained at Gaussian states).

Automated summary

In the realm of continuous-variable states and local Gaussian channels, the assumption that the optimal initial state with the most robust entanglement is Gaussian is proven to be false. Specific non-Gaussian two-mode states are shown to remain entangled under the effect of deterministic local attenuation or amplification. These results challenge the Gaussian world paradigm in quantum information science.