Multipartite Quantum Correlations in Open Quantum Systems

TL;DR

This paper introduces a new measure of multipartite quantum correlations applicable to various quantum correlation types, compares their robustness in open systems, and finds that initial entanglement influences which correlation type is more resilient.

Contribution

It defines a unified multipartite quantum correlation measure and analyzes its behavior for different states under dissipative dynamics, revealing the impact of initial entanglement.

Findings

QDs are more robust than entanglement in W states.

For GHZ states, entanglement of formation is more robust than quantum discord.

Multipartite entanglement influences the robustness of quantum correlations.

Abstract

In this paper we present a measure of quantum correlation for a multipartite system, defined as the sum of the correlations for all possible partitions. Our measure can be defined for quantum discord (QD), geometric quantum discord (GQD), or even by the entanglement of formation (EOF). For tripartite pure states, we show that the multipartite measure for the QD and the EOF are equivalent, which gives a way to compare the distribution and the robustness of these correlations in open quantum systems. We study dissipative dynamics for two distinct families of entanglement: a W state and a GHZ state. We show that, while for the W state the QD is more robust than the entanglement, for the GHZ state this is not true. It turns out that the initial genuine multipartite entanglement present in the GHZ state makes the EOF more robust than the QD.