The resistance of quantum entanglement to temperature in the Kugel-Khomskii model

TL;DR

This paper investigates the robustness of quantum entanglement against temperature effects in the Kugel-Khomskii model, revealing nonmonotonic temperature dependence and entanglement emergence at finite temperatures.

Contribution

It demonstrates that entanglement can be resilient to temperature changes and exhibits nonmonotonic behavior in the Kugel-Khomskii model, highlighting new insights into quantum correlations.

Findings

Entanglement persists over a wide temperature range.

Entanglement can appear at finite temperature even if absent at zero temperature.

Temperature dependence of entanglement can be nonmonotonic.

Abstract

The Kugel--Khomskii model with entangled spin and orbital degrees of freedom is a good testing ground for many important features in quantum information processing, such as robust gaps in the entanglement spectra. Here, we demonstrate that the entanglement can be also robust under effect of temperature within a wide range of parameters. It is shown, in particular, that the temperature dependence of entanglement often exhibits a nonmonotonic behavior. Namely, there turn out to be ranges of the model parameters, where entanglement is absent at zero temperature, but then, with an increase in temperature, it appears, passes through a maximum, and again vanishes.