Invariant Quantum Discord in Qubit-Qutrit Systems under Local Dephasing

TL;DR

This paper shows that in qubit-qutrit systems affected by local dephasing, quantum discord can remain unchanged over time even after entanglement vanishes, highlighting the robustness of quantum correlations beyond entanglement.

Contribution

It demonstrates the invariance of quantum discord in qubit-qutrit states under local dephasing, despite the finite-time disappearance of entanglement.

Findings

Quantum discord remains invariant under local dephasing.

Entanglement disappears in finite time.

Quantum correlations persist beyond entanglement loss.

Abstract

We investigate the dynamics of quantum discord and entanglement for a class of mixed qubit-qutrit states assuming that only the qutrit is under the action of a dephasing channel. We demonstrate that even though the entanglement in the qubit-qutrit state disappears in a finite time interval, partial coherence left in the system enables quantum discord to remain invariant throughout the whole time evolution.