Quantum correlations between each qubit in a two-atom system and the environment in terms of interatomic distance

TL;DR

This paper investigates how quantum correlations between two atoms and their environment vary with interatomic distance, revealing critical points where correlations are maximized or minimized, with implications for quantum information processing.

Contribution

It provides a quantitative analysis of quantum entanglement and discord between two atoms and their environment considering dipole interactions and collective damping effects.

Findings

Maximal quantum correlations occur at a specific interatomic distance.

Approaching atoms can enhance atom-environment entanglement.

Entanglement loss between atoms can be minimized at certain distances.

Abstract

The quantum correlations between a qubit and its environment are described quantitatively in terms of interatomic distance. Specifically, considering a realistic system of two two-level atoms and taking into account the dipole-dipole interaction and collective damping, the quantum entanglement and quantum discord are investigated, during the dissipative process, as a function of the interatomic distance. For atoms that are initially maximally entangled, it turns out that there is a critical distance where each atom is maximally quantum correlated with its environment. Counterintuitively, the approach of the two atoms can maximize the entanglement between each one and the environment and, even at the same distance, minimize the loss of entanglement between the pair.