Anomalous decay of quantum correlations of quantum dot qubits

TL;DR

This paper investigates how quantum correlations, measured by geometric discord, evolve in quantum dot qubits affected by phonon environments, revealing complex decay behaviors and robustness of correlations.

Contribution

It demonstrates that geometric discord exhibits unique decay patterns and is more resilient than entanglement under decoherence in quantum dot systems.

Findings

Geometric discord decays differently than entanglement, avoiding sudden death.

Quantum correlations can be enhanced by weak environment interactions.

Correlations show complex transitions and are sensitive to phase factors.

Abstract

We study the evolution of quantum correlations, quantified by the geometric discord, of two excitonic quantum dot qubits under the influence of the phonon environment. We show that the decay of these correlations differs substantially form the decay of entanglement. Instead of displaying sudden death type behavior, the geometric discord shows a tendency to undergo transitions between different types of decay, is sensitive to non-local phase factors, and may already be enhanced by weak environment-mediated interactions. Hence, two-qubit quantum correlations are more robust under decoherence processes, while showing a richer and more complex spectrum of behavior under unitary and non-unitary evolution.