Entanglement dynamics in a mechanically coupled double-cavity enhanced by two-level atomic ensembles.

We have explored the entanglement dynamics in a mechanically coupled double-cavity enhanced by two-level atomic ensembles. The entanglement between different components can be readily generated and transferred by appropriately choosing the parameters of two atomic ensembles, so that the maximal optomechanical entanglements for stable fixed points of the classical nonlinear counterpart of the system are ultimately achieved. Moreover, the entanglement generation scheme is robust with respect to the ambient temperature, in the sense that the maximal optomechanical entanglement is not completely lost up to T = 6 K. We further studied the time evolution of the entanglement in the parameter regimes where the fixed points are no longer stable, and observed that around the classical limit cycles, the optomechanical quantum entanglement also shows time-varying behavior about large average values. Our work has extended the usual time-invariant entanglement generation for stable fixed-point states to entanglement dynamics for more versatile steady states, and the proposed hybrid optomechanical system may serve as a flexible platform for quantum precision measurement as well as exploring the boundary between classical and quantum mechanics. • Stable optomechanical entanglements can be reached by adjusting suitable parameters. • Quantum entanglements on the boundary oscillate about higher average values. • In the unstable region, the entanglement is recovered by including atomic ensembles. • The scheme is readily extended to asymmetric cases for richer entanglement dynamics. [ABSTRACT FROM AUTHOR]