Geometric Bell-like inequalities for steering

TL;DR

This paper introduces geometric Bell-like inequalities that effectively detect quantum steering by distinguishing steerable states from non-steering correlations, using all measurement settings.

Contribution

The authors develop new Bell-like inequalities with lower bounds for non-steering correlations, providing a comprehensive criterion for steerability of two-qubit states.

Findings

Inequalities involve all measurement settings at each side.

Conditions for steerability are elegant and applicable to arbitrary two-qubit states.

Inequalities improve detection of quantum steering over standard Bell inequalities.

Abstract

Many of the standard Bell inequalities (e.g., CHSH) are not effective for detection of quantum correlations which allow for steering, because for a wide range of such correlations they are not violated. We present Bell-like inequalities which have lower bounds for non-steering correlations than for local causal models. The inequalities involve all possible measurement settings at each side. We arrive at interesting and elegant conditions for steerability of arbitrary two-qubit states.