Thermal entanglement in the nanotubular system Na_2V_3O_7

TL;DR

This paper uses magnetic susceptibility measurements to estimate the temperature below which thermal entanglement exists in Na₂V₃O₇, finding it persists up to approximately 365 K, significantly higher than bipartite entanglement temperatures.

Contribution

It applies a universal entanglement witness based on magnetic susceptibility to a nanotubular system, providing a novel estimate of the critical temperature for thermal entanglement.

Findings

Thermal entanglement in Na₂V₃O₇ persists up to about 365 K.

The estimated critical temperature is roughly three times higher than bipartite entanglement temperature.

Experimental susceptibility data effectively reveal quantum correlations at high temperatures.

Abstract

Macroscopic entanglement witnesses have been put forward recently to reveal nonlocal quantum correlations between individual constituents of the solid at nonzero temperatures. Here we apply a recently proposed universal entanglement witness, the magnetic susceptibility [New J. Phys. {\bf 7}, 258 (2005)] for the estimation of the critical temperature $T_c$ in the nanotubular system ${\rm Na_2V_3O_7}$ below which thermal entanglement is present. As a result of an analysis based on the experimental data for dc-magnetic susceptibility, we show that $T_c \approx 365$ K, which is approximately three times higher than the critical temperature corresponding to the bipartite entanglement.