Locking and unlocking of quantum nonlocality without entanglement in local discrimination of quantum states

TL;DR

This paper investigates how post-measurement information can control the presence of nonlocality without entanglement in quantum state discrimination, revealing new ways to manipulate quantum nonlocality.

Contribution

It demonstrates that post-measurement information can both lock and unlock nonlocality without entanglement in optimal unambiguous discrimination, extending previous findings.

Findings

Post-measurement information influences NLWE in unambiguous discrimination.

Post-measurement info can lock or unlock NLWE.

Potential applications in quantum information hiding and sharing.

Abstract

The phenomenon of nonlocality without entanglement(NLWE) arises in discriminating multi-party quantum separable states. Recently, it has been found that the post-measurement information about the prepared subensemble can lock or unlock NLWE in minimum-error discrimination of non-orthogonal separable states. Thus, it is natural to ask whether the availability of the post-measurement information can influence on the occurrence of NLWE even in other state-discrimination strategies. Here, we show that the post-measurement information can be used to lock as well as unlock the occurrence of NLWE in terms of optimal unambiguous discrimination. Our results can provide a useful application for hiding or sharing information based on non-orthogonal separable states.