Quantum correlations as precursors of entanglement

TL;DR

This paper demonstrates that in a system of two excited qubits interacting with a common reservoir, quantum and classical correlations emerge before entanglement, revealing a temporal sequence in correlation development.

Contribution

It shows that quantum and classical correlations precede entanglement in a dipole-interacting qubit system with a common reservoir, highlighting the dynamics of correlation emergence.

Findings

Quantum and classical correlations appear before entanglement.

Entanglement develops after a time lag following initial correlations.

Different measures of quantum correlations show coincident dynamics.

Abstract

We show that for two initially excited qubits, interacting via dipole forces and with a common reservoir, entanglement is preceded by the emergence of quantum and classical correlations. After a time lag, entanglement finally starts building up, giving rise to a peculiar entangled state, with very small classical correlations. Different measures of quantum correlations are discussed, and their dynamics are compared and shown to lead to coincident values of these quantifiers for several ranges of time.