Optimal resource states for local state discrimination

Optimal resource states for local state discrimination

We study the problem of locally distinguishing pure quantum states using shared entanglement as a resource. For a given set of locally indistinguishable states we define a resource state to be useful if it can enhance local distinguishability and optimal if it can distinguish the states as well as global measurements and is also minimal with respect to a partial ordering defined by entanglement...

Optimal local discrimination of two multipartite pure states

In a recent paper, Walgate et al. (Phys. Rev. Lett. 85 (2000) 4972) demonstrated that any two orthogonal multipartite pure states can be optimally distinguished using only local operations. We utilise their result to show that this is true for any two multipartite pure states, in the sense of inconclusive discrimination. There are also certain regimes of conclusive discrimination for which the ...

Optimal sequential measurements for bipartite state discrimination

When do Local Operations and Classical Communication Suffice for Optimal Quantum State Discrimination?

In this talk we consider when an ensemble of states can be optimally distinguished by local operations and classical communication (LOCC). It is shown that almost all two-qubit ensembles consisting of three pure states cannot be optimally discriminated using LOCC. This is surprising since any two pure states can be distinguished optimally by LOCC. Additionally, we prove an easy sufficient condi...

Asymptotically Optimal Discrimination between Pure Quantum States

We consider the decision problem between a finite number of states of a finite quantum system, when an arbitrarily large number of copies of the system is available for measurements. We provide an upper bound on the exponential rate of decay of the averaged probability of rejecting the true state. It represents a generalized quantum Chernoff distance of a finite set of states. As our main resul...