Post Markovian Dynamics of Quantum Correlations: Entanglement vs. Discord

TL;DR

This paper investigates the post-Markovian dynamics of quantum correlations in a two-qubit system, revealing that quantum discord is more robust than entanglement and can be maintained at high temperatures, with implications for quantum dot systems.

Contribution

It introduces a detailed model of two-qubit dynamics in a post-Markovian environment considering spin-orbit interaction and magnetic field inhomogeneity, highlighting the robustness of quantum discord.

Findings

Quantum discord remains more robust than entanglement during evolution.

Asymmetries due to magnetic field and temperature differences affect quantum discord.

Quantum correlations can be preserved at high temperatures with proper parameters.

Abstract

Dynamics of an open two-qubit system is investigated in the post-Markovian regime, where the environments have a short-term memory. Each qubit is coupled to separate environment which is held in its own temperature. The inter-qubit interaction is modeled by XY-Heisenberg model in the presence of spin-orbit interaction and inhomogeneous magnetic field. The dynamical behavior of entanglement and discord has been considered. The results show that, quantum discord is more robust than quantum entanglement, during the evolution. Also the asymmetric feature of quantum discord can be monitored by introducing the asymmetries due to inhomogeneity of magnetic field and temperature difference between the reservoirs. By employing proper parameters of the model, it is possible to maintain non-vanishing quantum correlation at high degree of temperature. The results can provide a useful recipe for studying of dynamical behavior of two-qubit systems such as trapped spin-electrons in coupled quantum dots.