Steady-state entanglement and normal-mode splitting in an atom-assisted optomechanical system with intensity-dependent coupling

TL;DR

This paper theoretically investigates bipartite and tripartite continuous variable entanglement and normal-mode splitting in an atom-assisted optomechanical system with intensity-dependent coupling, revealing conditions for entanglement generation and mode splitting.

Contribution

It introduces a novel tripartite Hamiltonian for an atom-field-mirror system with intensity-dependent coupling and analyzes entanglement sharing and mode splitting phenomena.

Findings

Bipartite entanglement can be generated between any pair of the three subsystems.

Atom-mirror entanglement is enhanced at the expense of other entanglements.

Normal mode splitting into three modes occurs when the Lamb-Dicke parameter is sufficiently large.

Abstract

In this paper, we study theoretically the bipartite and tripartite continuous variable entanglement as well as the normal-mode splitting in a single-atom cavity optomechanical system with intensity-dependent coupling. The system under consideration is formed by a Fabry-Perot cavity with a thin vibrating end mirror and a two-level atom in the Gaussian standing-wave of the cavity mode. We first derive the general form of Hamiltonian describing the tripartite intensity-dependent atom-field-mirror coupling due to the presence of cavity mode structure. We then restrict our treatment to the first vibrational sideband of the mechanical resonator and derive a novel form of tripartite atom-field-mirror Hamiltonian. We show that when the optical cavity is intensely driven one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, the atom-mirror entanglement is efficiently generated at the expense of optical-mechanical and optical-atom entanglement. We also find that in such a system, when the Lamb-Dicke parameter is large enough one can simultaneously observe the normal mode splitting into three modes.