Entanglement activation and the robustness of quantum correlations
Fernando G. S. L. Brandão · Physical Review A · 2007
We show that the usefulness of a state as an activator in teleportation protocols is equivalent to the robustness of its entanglement to noise. The robustness of entanglement of a bipartite state $\ensuremath{\sigma}$ is linked to the maximum increase in the fidelity of teleportation of any other state when $\ensuremath{\sigma}$ is used as an extra resource. On the one hand, this connection gives an operational meaning to the robustness of entanglement. On the other hand, it shows that the activation capability---which has a central role as an operational way of quantifying bound entangled states---can be estimated experimentally by measuring entanglement witnesses.