Invariant entanglement and generation of quantum correlations under global dephasing

TL;DR

This paper explores how quantum entanglement and correlations behave under collective dephasing in two-qubit systems, revealing regions with invariant entanglement and analyzing their dynamics.

Contribution

It introduces a geometric approach to identify regions with time-invariant entanglement and studies the relation between entanglement and local quantum uncertainty.

Findings

Existence of regions with frozen entanglement during dynamics

Generation of local quantum uncertainty alongside invariant entanglement

Different dynamical behaviors of local quantum uncertainty identified

Abstract

We investigate the dynamics of quantum entanglement and more general quantum correlations quantified respectively via negativity and local quantum uncertainty for two qubit systems undergoing Markovian collective dephasing. Focusing on a two-parameter family of initial two-qubit density matrices, we study the relation of the emergence of the curious phenomenon of time-invariant entanglement and the dynamical behavior of local quantum uncertainty. Developing an illustrative geometric approach, we demonstrate the existence of distinct regions of quantum entanglement for the considered initial states and identify the region that allows for completely frozen entanglement throughout the dynamics, accompanied by generation of local quantum uncertainty. Furthermore, we present a systematic analysis of different dynamical behaviors of local quantum uncertainty such as its sudden change or smooth amplification, in relation with the dynamics of entanglement.