Entropic Nonsignaling Correlations

We introduce the concept of entropic nonsignaling correlations, i.e., entropies arising from probabilistic theories that are compatible with the fact that we cannot transmit information instantaneously. We characterize and show the relevance of these entropic correlations in a variety of different scenarios, ranging from typical Bell experiments to more refined descriptions such as bilocality and information causality. In particular, we apply the framework to derive the first entropic inequality testing genuine tripartite nonlocality in quantum systems of arbitrary dimension and also prove the first known monogamy relation for entropic Bell inequalities. Further, within the context of complex Bell networks, we show that entropic nonlocal correlations can be activated.

Figure 1

Pictorial illustration of the NS entropic cone.

Figure 2

The violation of inequality $S_{\mathrm{L}|\mathrm{NS}}\ge 0$ using Greenberger-Horne-Zeilinger (GHZ) states. The points stand for the violation obtained via numerical optimization.