Quantum entanglement and disentanglement of multi-atom systems

TL;DR

This review discusses recent advances in understanding quantum entanglement in multi-atom systems, focusing on entanglement creation, evolution, and disentanglement, especially through spontaneous emission and environmental interactions.

Contribution

It provides a comprehensive overview of entanglement dynamics in atomic systems, highlighting new insights into spontaneous emission's role and methods for controlling entanglement evolution.

Findings

Spontaneous emission can induce entanglement under certain conditions.

Entanglement exhibits sudden death and revival phenomena.

Methods for preparing and steering long-lived entangled states are discussed.

Abstract

We present a review of recent research on quantum entanglement, with special emphasis on entanglement between single atoms, processing of an encoded entanglement and its temporary evolution. Analysis based on the density matrix formalism are described. We give a simple description of the entangling procedure and explore the role of the environment in creation of entanglement and in disentanglement of atomic systems. A particular process we will focus on is spontaneous emission, usually recognized as an irreversible loss of information and entanglement encoded in the internal states of the system. We illustrate some certain circumstances where this irreversible process can in fact induce entanglement between separated systems. We also show how spontaneous emission reveals a competition between the Bell states of a two qubit system that leads to the recently discovered "sudden" features in the temporal evolution of entanglement. An another problem illustrated in details is a deterministic preparation of atoms and atomic ensembles in long-lived stationary squeezed states and entangled cluster states. We then determine how to trigger the evolution of the stable entanglement and also address the issue of a steered evolution of entanglement between desired pairs of qubits that can be achieved simply by varying the parameters of a given system.