Behavior of Quantum Correlations under Local Noise

TL;DR

This paper investigates how quantum correlations evolve under local noisy channels, revealing that noise can sometimes generate rather than destroy quantum correlations, especially in higher-dimensional systems.

Contribution

It demonstrates that unital channels always decrease quantum correlations in qubits, but non-unital channels can create correlations, and higher-dimensional systems may see increased correlations from local noise.

Findings

Quantum correlations decrease under unital channels for qubits.

Non-unital channels can generate quantum correlations from classical states.

Higher-dimensional systems can have increased quantum correlations due to local noise.

Abstract

We characterize the behavior of quantum correlations under the influence of local noisy channels. Intuition suggests that such noise should be detrimental for quantumness. When considering qubit systems, we show for which channel this is indeed the case: the amount of quantum correlations can only decrease under the action of unital channels. However, non-unital channels (e.g. such as dissipation) can create quantum correlations for some initially classical state. Furthermore, for higher-dimensional systems even unital channels may increase the amount of quantum correlations. Thus, counterintuitively, local decoherence can generate quantum correlations.