Casimir-force-assisted ground-state cooling and macroscopic quantum coherence

Abstract

We theoretically investigate the ground-state cooling and macroscopic quantum coherence of the mechanical motion in a hybrid optomechanical system with a movable cavity wall and a nearby oscillation nanosphere. In the study, the vacuum effect is used to realize a direct coupling between the movable cavity wall and the oscillation nanosphere, which plays a role in the energy transfer channel between them. We find that when the Casimir force between the mechanical oscillators is included, the ground-state cooling and the macroscopic quantum coherence of the oscillation nanosphere can be realized in a certain range of effective detuning and driving power. We discuss in detail the dependence of the quantum properties on the amplitude of Casimir force, the driving power, the optical effective detuning and the oscillation frequency of the movable mirror. The results suggest that the quantum phenomenon of a single nanosphere can be manipulated by coupling an optomechanical cavity to the nanosphere and therefore has a potential application in quantum optics and the utilization of vacuum force.

Keywords

• Optomechanical system
• Ground-state cooling
• Quantum coherence
• Casimir force