Dissipative dynamics of atom-field entanglement in the ultrastrong-coupling regime

TL;DR

This paper investigates the dissipative dynamics of atom-field entanglement in the ultrastrong-coupling regime beyond the rotating wave approximation, revealing steady-state entanglement growth with coupling strength.

Contribution

It introduces a method to analyze entanglement dynamics beyond RWA using monogamic relations and bounds, showing steady-state entanglement in the strong-coupling regime.

Findings

Atom-field entanglement exists in steady states beyond RWA.

Entanglement increases with stronger atom-field coupling.

Steady-state entanglement is present in the ultrastrong-coupling regime.

Abstract

The dynamics of atom-field entanglement for a system composed of two atoms resonantly coupled to a single mode leaky cavity field has been investigated beyond rotating wave approximation (RWA). By using monogamic relation for entanglement of formation (EOF) as well as the lower bound of EOF for bipartite mixed states in higher dimensions, contrary to the RWA case, the atom-field system in the steady states is found to be entangled in the strong-coupling regime and the entanglement can grow as a function of atom-field coupling strength.