Experimental Determination of Thermal Entanglement in Spin Clusters using Magnetic Susceptibility Measurements

TL;DR

This study experimentally detects thermal entanglement in a spin cluster compound using magnetic susceptibility, revealing pairwise and tripartite entanglement at specific temperature ranges, supported by theoretical analysis.

Contribution

It provides the first experimental evidence of thermal entanglement in a real material using magnetic susceptibility measurements.

Findings

Pairwise entanglement observed below ~200 K.

Tripartite entanglement observed below ~240 K.

Theoretical analysis of entanglement evolution with field and temperature.

Abstract

The present work reports an experimental observation of thermal entanglement in a clusterized spin chain formed in the compound Na$_2$Cu$_5$Si$_4$O$_{14}$. The presence of entanglement was investigated through two measured quantities, an Entanglement Witness and the Entanglement of Formation, both derived from the magnetic susceptibility. It was found that pairwise entanglement exists below $ \sim 200$ K. Tripartite entanglement was also observed below $ \sim 240$ K. A theoretical study of entanglement evolution as a function of applied field and temperature is also presented.