Asymmetric One-Sided Semi-Device-Independent Steerability of Quantum Discordant States

TL;DR

This paper demonstrates that superunsteerability can occur in quantum states with one-way quantum discord, showing that superunsteerability does not require superlocality and can exist in a semi-device-independent context.

Contribution

It reveals that superunsteerability can be exhibited by one-way quantum discordant states, expanding understanding of quantum correlations beyond superlocality.

Findings

Superunsteerability occurs in one-way quantum discordant states.

Superunsteerability can exist without superlocality.

One-way steerability can occur in a semi-device-independent manner.

Abstract

Superlocality and superunsteerability provide operational characterization of quantum correlations in certain local and unsteerable states respectively. Such quantum correlated states have a nonzero quantum discord. A two-way nonzero quantum discord is necessary for quantum correlations pointed out by superlocality. On the other hand, in this work, we demonstrate that a two-way nonzero quantum discord is not necessary to demonstrate superunsteerability. To this end, we demonstrate superunsteerability for one-way quantum discordant states. This in turn implies the existence of one-way superunsteerability and also the presence of superunsteerability without superlocality. Superunsteerability for nonzero quantum discord states implies the occurence of steerability in a one-sided semi-device-independent way. Just like one-way steerability occurs for certain Bell-local states in a one-sided device-independent way, our result shows that one-way steerability can also occur for certain nonsuperlocal states but in a one-sided semi-device-independent way.