Geometric quantum discord and non-Markovianity of structured reservoirs

TL;DR

This paper explores how non-Markovian effects in structured reservoirs influence geometric quantum discord in two-qubit systems, revealing that information backflow can enhance quantum correlations and serve as a resource for their protection.

Contribution

It establishes a connection between information flow direction and geometric quantum discord variation, demonstrating non-Markovianity's role in enhancing quantum correlations in structured reservoirs.

Findings

Non-Markovianity correlates with increased GQDs in most parameter regions.

Information backflow from reservoirs enhances quantum discord.

Reservoir spectral structures influence the degree of GQD enhancement.

Abstract

The reservoir memory effects can lead to information backflow and recurrence of the previously lost quantum correlations. We establish connections between the direction of information flow and variation of the geometric quantum discords (GQDs) measured respectively by the trace distance, the Hellinger distance, and the Bures distance for two qubits subjecting to the bosonic structured reservoirs, and unveil their dependence on a factor whose derivative signifies the (non-)Markovianity of the dynamics. By considering the reservoirs with Lorentzian and Ohmic-like spectra, we further demonstrated that the non-Markovianity induced by the backflow of information from the reservoirs to the system enhances the GQDs in most of the parameter regions. This highlights the potential of non-Markovianity as a resource for protecting the GQDs.