All entangled states are useful for channel discrimination

TL;DR

This paper proves that all entangled states can enhance the performance of quantum channel discrimination tasks, showing their universal usefulness as a resource in quantum information processing.

Contribution

It establishes that every entangled state can outperform separable states in some channel discrimination scenario, highlighting the fundamental role of entanglement.

Findings

Every entangled state improves channel discrimination success probability.

No separable state can match the advantage provided by entangled states.

The result applies to single-copy bipartite entangled states.

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.