Minimal auxiliary entanglement for nondestructive multipartite state discrimination

Determine the minimal auxiliary entanglement required to discriminate orthogonal multipartite quantum states by local operations and classical communication while preserving the states’ intrinsic multipartite entanglement.

Background

The paper studies the resource cost of discriminating mutually orthogonal quantum states under local operations and classical communication (LOCC), with particular emphasis on protocols that preserve the entanglement of the states being identified. Although auxiliary entanglement can enable local discrimination and the paper derives several results for Bell states and maximally or nonmaximally entangled GHZ-state ensembles, the general minimum auxiliary entanglement needed for nondestructive discrimination of orthogonal multipartite states is not determined.

The stated problem concerns both the amount and type of auxiliary entanglement required when the target states’ intrinsic multipartite correlations must remain intact. Establishing this minimum would clarify the resource-theoretic cost of entanglement-preserving state discrimination beyond the specific GHZ constructions analyzed in the paper.