Dynamical bipartite and tripartite entanglement of mechanical oscillators in an optomechanical array

Abstract

We theoretically propose a method to generate tripartite entanglement of three mechanical oscillators in an optomechanical array. We consider a system comprised of three bichromatically driven optomechanical systems which are coupled to each other via Coulomb interaction of the mechanical oscillators. We show that, for small Coulomb coupling strength, steady tripartite entanglement of the three mechanical oscillators with time periodicity can be generated due to the combined effect of the two-tone drivings and the Coulomb coupling. At large Coulomb coupling strength, the tripartite entanglement exhibits steady entanglement sudden death and revival. The duration of entanglement death during one period can be controlled by the Coulomb coupling strength. The tripartite entanglement is robust against the mechanical thermal noise. Our paper provides us a route for exploring and exploiting controllable and robust multipartite entanglement among macroscopic mechanical oscillators.