Sudden change of geometric quantum discord in finite temperature reservoirs

TL;DR

This paper studies how geometric quantum discord measures exhibit sudden changes in two-qubit systems under thermal reservoirs, revealing differences based on the measure used and the state properties.

Contribution

It demonstrates that different geometric quantum discord measures behave differently under thermal noise, highlighting their incompatibility in characterizing quantum correlations.

Findings

Different GQDs show distinct sudden change behaviors.

Thermal reservoirs can alter the ordering of quantum states according to GQDs.

GQDs are incompatible in characterizing quantum correlations quantitatively and qualitatively.

Abstract

We investigate sudden change (SC) behaviors of the distance-based measures of geometric quantum discords (GQDs) for two non-interacting qubits subject to the two-sided and the one-sided thermal reservoirs. We found that the GQDs defined by different distances exhibit different SCs, and thus the SCs are the combined result of the chosen discord measure and the property of a state. We also found that the thermal reservoir may generate states having different orderings related to different GQDs. These inherent differences of the GQDs reveal that they are incompatible in characterizing quantum correlations both quantitatively and qualitatively.