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.