Postmeasurement information and nonlocality of quantum state discrimination

TL;DR

This paper explores how postmeasurement information can influence the nonlocality in quantum state discrimination, showing that the choice of subensembles can either create or annihilate nonlocality.

Contribution

It establishes conditions under which postmeasurement information affects nonlocality and provides examples of quantum states illustrating these effects.

Findings

Postmeasurement information can create or destroy nonlocality.

The effect depends on the choice of subensembles.

Examples of bipartite states demonstrate these phenomena.

Abstract

In quantum state discrimination, nonlocality arises when the optimal state discrimination cannot be realized by local operations and classical communication. Recently, it has been found that the postmeasurement information about the subensemble containing the prepared state can annihilate or create nonlocality in quantum state discrimination. Here, we show that annihilation or creation of nonlocality in quantum state discrimination can depend on the choice of subensembles provided by postmeasurement information. We establish sufficient conditions that annihilating or creating nonlocality depends on the choice of subensembles provided by postmeasurement information. We further provide bipartite quantum state ensembles satisfying these conditions to illustrate our results.