Multipartite entanglement serves as a faithful detector for quantum phase transitions

Abstract

We investigate quantum phase transitions in various spin chain systems using the multipartite entanglement measure $\tau_{SEF}$
based on the monogamy inequality of squared entanglement of formation. Our results demonstrate that $\tau_{SEF}$ is more
effective and reliable than bipartite entanglement or bipartite correlation measures such as entanglement of formation, von Neumann
entropy, and quantum discord in characterizing quantum phase transitions. $\tau_{SEF}$ not only detects critical points that may
go unnoticed by other detectors but also avoids the issue of singularity at non-critical points encountered by other measures.
Furthermore, by applying $\tau_{SEF}$, we have obtained the phase diagram for the XY spin chain with three and four interactions and discovered a new quantum phase.

Interconversion between block coherence and multipartite entanglement in many-body systems

“…In this section, we study the resource conversion from block coherence to multipartite entanglement via multipartite block-incoherent operations. In comparison to bipartite entanglement, multipartite entanglement can characterize some special tasks in multi-party systems, such as multipartite entanglement dynamics [36][37][38][39][40], quantum phase transitions [41][42][43][44][45], and so on. On the other hand, we noted that multipartite block-incoherent operations are not equivalent to those of the bipartite case in general, since the multipartite operations have the ability to generate multipartite entangled states (see the details in appendix A).…”