Thermal entanglement witness for materials with variable local spin lengths

TL;DR

This paper introduces a generalized thermal entanglement witness that can be used experimentally to detect entanglement in materials with variable local spin lengths, including conductors and insulators.

Contribution

It extends the thermal entanglement witness to systems with variable local spins, enabling experimental detection in a broader class of materials.

Findings

Entanglement is favored by electron itinerancy.

Weak dependence of entanglement on external spin degrees.

Method applicable to both conductors and insulators.

Abstract

We show that the thermal entanglement in a spin system using only magnetic susceptibility measurements is restricted to the insulator materials. We develop a generalization of the thermal entanglement witness that allows us to get information about the system entanglement with variable local spin lengths that can be used experimentally in conductor or insulator materials. As an application, we study thermal entanglement for the half-filled Hubbard model for linear, square and cubic clusters. We note that it is the itinerancy of electrons that favors the entanglement. Our results suggest a weak dependence between entanglement and external spin freedom degrees.