Modeling and control of entanglement dynamics in laser cooling of trapped atoms

TL;DR

This paper analyzes the entanglement dynamics in laser cooling of trapped atoms, using a two-state model and non-Hermitian extension to understand and control entanglement behavior during the cooling process.

Contribution

It introduces a simplified two-state Landau-Zener model and an effective non-Hermitian Hamiltonian to explain and control entanglement in EIT laser cooling.

Findings

Entanglement dynamics can be understood via a two-state Landau-Zener model.

Spontaneous emission causes decay of entanglement, modeled by a non-Hermitian Hamiltonian.

Permanent entanglement can be achieved by rapid switching off of driving fields.

Abstract

We discuss the dynamical behavior of the entanglement between the internal and the external degrees of freedom of a trapped atom in electromagnetically-induced transparency (EIT) laser cooling. It is shown that essential features of the intricate entanglement dynamics observed in full numerical simulations of the underlying quantum master equation can be understood in terms of a two-state model on the basis of Landau-Zener splittings in the atom-laser field Hamiltonian. An extension of this model to an effective non-Hermitian Hamiltonian is constructed which describes the decay of entanglement by spontaneous emission processes. We also discuss schemes for the control of entanglement and demonstrate that a permanent entanglement can be imprinted on trapped atoms through a rapid switch off of the driving fields. Finally, we point out fundamental distinctions between the entanglement created in EIT cooling and in the cooling scheme based on velocity-selective coherent population trapping.