All entangled states are useful for channel discrimination

Phys Rev Lett. 2009 Jun 26;102(25):250501. doi: 10.1103/PhysRevLett.102.250501. Epub 2009 Jun 24.

Abstract

We prove that every entangled state is useful as a resource for the problem of minimum-error channel discrimination. More specifically, given a single copy of an arbitrary bipartite entangled state, it holds that there is an instance of a quantum channel discrimination task for which this state allows for a correct discrimination with strictly higher probability than every separable state.