Thermal robustness of multipartite entanglement of the 1-D spin 1/2 XY model

TL;DR

This paper investigates how multipartite entanglement in the 1-D spin 1/2 XY model withstands thermal excitations, identifying a threshold temperature that indicates the persistence of entanglement under thermal effects.

Contribution

It introduces a method to determine the threshold temperature for entanglement robustness using the geometric measure of entanglement in the XY model.

Findings

Identifies regions with high but fragile entanglement at zero temperature.

Finds regions with low but thermally robust entanglement.

Reveals phase diagram lines related to entanglement thresholds.

Abstract

We study the robustness of multipartite entanglement of the ground state of the one-dimensional spin 1/2 XY model with a transverse magnetic field in the presence of thermal excitations, by investigating a threshold temperature, below which the thermal state is guaranteed to be entangled. We obtain the threshold temperature based on the geometric measure of entanglement of the ground state. The threshold temperature reflects three characteristic lines in the phase diagram of the correlation function. Our approach reveals a region where multipartite entanglement at zero temperature is high but is thermally fragile, and another region where multipartite entanglement at zero temperature is low but is thermally robust.