Entanglement witness and nonlocality in confidence of measurement from multipartite quantum state discrimination

TL;DR

This paper explores the relationship between entanglement witnesses and quantum nonlocality in multipartite state discrimination, establishing bounds and methods to construct ensembles with nonlocal measurement confidence.

Contribution

It introduces a new connection between entanglement witnesses and measurement confidence, providing bounds and a method to construct nonlocal ensembles.

Findings

Maximum confidence depends on entanglement witness existence

Conditions for upper bounds on local confidences are provided

Method to construct ensembles with nonlocal maximum confidences

Abstract

We consider multipartite quantum state discrimination and provide a specific relation between the properties of entanglement witness and quantum nonlocality inherent in the confidence of measurements. We first provide the definition of the confidence of measurements as well as its useful properties for various types of multipartite measurements. We show that globally maximum confidence that cannot be achieved by local operations and classical communication strongly depends on the existence of entanglement witness. We also provide conditions for an upper bound on maximum of locally-achievable confidences. Finally, we establish a method in terms of entanglement witness to construct quantum state ensemble with nonlocal maximum confidences.