Managing the three-party entanglement challenge. Issue 4 (2nd October 2021)

• Record Type: Journal Article
• Authors: Xie, Songbo; Eberly, J.H.
• Is Part Of: Contemporary physics. Volume 62:Issue 4(2021)
• Page Start: 189
• Page End: 198
• Publication Date: 2021-10-02
• Subjects: Qubit systems -- multipartite entanglement -- triangle measure -- concurrence Fill; Physics -- Periodicals; 530
• DOI: 10.1080/00107514.2022.2104425
• Languages: English
• ISSNs: 0010-7514

Abstract

Abstract : We introduce the challenges of multi-party quantum entanglement and explain a recent success in learning to take its measure. Given the widely accepted reputation of entanglement as a counter-intuitive feature of quantum theory, we first describe pure-state entanglement itself. We restrict attention to multi-party qubit states. Then we introduce the features that have made it challenging for several decades to extend an entanglement measure beyond the 2-qubit case of Bell states. We finish with a description of the current understanding that solves the 3-qubit entanglement challenge. This necessarily takes into account the fundamental division of the 3-qubit state space into two completely independent sectors identified with the so-called GHZ and W states.