Correlation tensor criteria for genuine multiqubit entanglement

TL;DR

This paper introduces a geometric method using correlation tensors to detect genuine multiqubit entanglement, enabling practical and broad detection with fewer measurements compared to traditional witnesses.

Contribution

It develops a novel geometric approach with non-linear criteria based on correlation tensors for efficient multiqubit entanglement detection.

Findings

Criteria involve observable quantities

Detects entanglement in wide classes of states

Requires few specific measurements

Abstract

We present a development of a geometric approach to entanglement indicators. The method is applied to detect genuine multiqubit entanglement. The criteria are given in form of non-linear conditions imposed on correlation tensors. Thus they involve directly observable quantities, and in some cases require only few specific measurements to find multiqubit entanglement. The non-linearity of each of the criteria allows detection of entanglement in wide classes of states. In contrast to entanglement witnesses, which in the space of Hermitian operators define a hyperplane, the new conditions define a geometric figure encapsulating the non-fully entangled states within it.