Entanglement detection via condition of quantum correlation

TL;DR

This paper introduces a new necessary condition for quantum correlation that leads to noise-resistant Bell inequalities and entanglement witnesses, enabling efficient detection of high-dimensional and multipartite entanglement with fewer measurements.

Contribution

It presents a novel necessary condition for quantum correlation, resulting in efficient Bell inequalities and entanglement witnesses for high-dimensional and multipartite states with reduced measurement complexity.

Findings

Derived a $d$-level bipartite Bell inequality with $O(d)$ measurements

Connected Bell inequalities with entanglement witnesses for high-dimensional states

Proposed robust entanglement witnesses for multipartite states

Abstract

We develop a novel necessary condition of quantum correlation. It is utilized to construct $d$-level bipartite Bell-type inequality which is strongly resistant to noise and requires only analyses of $O(d)$ measurement outcomes compared to the previous result $O(d^{2})$. Remarkably, a connection between the arbitrary high-dimensional bipartite Bell-type inequality and entanglement witnesses is found. Through the necessary condition of quantum correlation, we propose that the witness operators to detect truly multipartite entanglement for a generalized Greenberger-Horne-Zeilinger (GHZ) state with two local measurement settings and a four-qubit singlet state with three settings. Moreover, we also propose the first robust entanglement witness to detect four-level tripartite GHZ state with only two local measurement settings.