More Entanglement Implies Higher Performance in Channel Discrimination Tasks

Abstract

We show that every entangled state provides an advantage in ancilla-assisted bi- and multichannel discrimination that singles out its degree of entanglement, quantified in terms of the Schmidt number. The Schmidt-number robustness provides a compelling quantification of such an advantage, and, remarkably, the well-known robustness of entanglement exactly provides the largest multiplicative advantage an entangled state can provide compared to the case where no ancilla is used in a channel discrimination task.