Thermal entanglement of Hubbard dimers in the nonextensive statistics

TL;DR

This paper investigates how nonextensive statistical mechanics affects thermal entanglement in Hubbard dimers, revealing that the entropic index significantly influences entanglement properties and survival at higher temperatures.

Contribution

It introduces the application of nonextensive statistics to analyze thermal entanglement in Hubbard dimers, highlighting the dependence on the entropic index and exploring physical interpretations.

Findings

Entanglement threshold temperature increases for q<1.

Thermal entanglement depends strongly on the entropic index q.

Relations among correlation measures are elucidated.

Abstract

The thermal entanglement of the Hubbard dimer (two-site Hubbard model) has been studied with the nonextensive statistics. We have calculated the auto-correlation ($O_q$), pair correlation ($L_q$), concurrence ($\Gamma_q$) and conditional entropy ($R_q$) as functions of entropic index $q$ and the temperature $T$. The thermal entanglement is shown to considerably depend on the entropic index. For $q < 1.0$, the threshold temperature where $\Gamma_q$ vanishes or $R_q$ changes its sign is more increased and the entanglement may survive at higher temperatures than for $q=1.0$. Relations among $L_q$, $\Gamma_q$ and $R_q$ are investigated. The physical meaning of the entropic index $q$ is discussed with the microcanonical and superstatistical approaches. The nonextensive statistics is applied also to Heisenberg dimers.