Quantum correlations dynamics under different non-markovian environmental models

TL;DR

This paper studies how different environmental models affect the dynamics of quantum correlations in a two-qubit system, revealing that in strong coupling, non-Markovianity, not spectral density, governs correlation behavior.

Contribution

It compares multiple environmental models and uncovers the dominant factors influencing quantum correlation dynamics in different coupling regimes.

Findings

Weak coupling: decay speed depends on spectral density functions.

Strong coupling: quantum correlation dynamics depend on non-Markovianity.

In strong coupling, spectral density functions are less influential.

Abstract

We investigate the roles of different environmental models on quantum correlation dynamics of two-qubit composite system interacting with two independent environments. The most common environmental models (the single-Lorentzian model, the squared-Lorentzian model, the two-Lorentzian model and band-gap model) are analyzed. First, we note that for the weak coupling regime, the monotonous decay speed of the quantum correlation is mainly determined by the spectral density functions of these different environments. Then, by considering the strong coupling regime we find that, contrary to what is stated in the weak coupling regime, the dynamics of quantum correlation depends on the non-Markovianity of the environmental models, and is independent of the environmental spectrum density functions.