原子-光力混合系统的机械压缩和纠缠研究

Study on Mechanical Squeezing and Entanglement of Hybrid Atom-Optomechanical Systems

传统光力系统中产生强机械压缩一般需要光场衰减率小于机械振子频率(可分辨边带条件),在实验室极难实现。针对光力系统在高不可分辨边带(光场衰减率远大于机械振子频率)条件下产生强机械压缩及稳态纠缠问题,提出利用两个两能级原子系综和两束不同强度激光共同调制光力系统,放宽可分辨边带条件的限制。研究结果表明:将两个原子系综放入光力学系统中,即使在高不可分辨的边带状态下,也能实现超过3 dB的强机械压缩;光场和机械振子之间的稳态纠缠也可产生。

In a typical optomechanical system,the decay rate of an optical cavity must be smaller than the frequency of a mechanical oscillator(resolved sideband regime)in order to generate strong mechanical squeezing generally.This is difficult to implement in experiments.A scheme is proposed to generate strong mechanical squeezing and steady state entanglement in a hybrid atom-optomechanical system in the highly unresolved sideband regime(the decay rate of the optical cavity is much larger than the frequency of the mechanical oscillator).Two two-level atomic ensembles and two lasers with different amplitudes can be used to control the optomechanical system and the resolved sideband limit can be relaxed.Our results are as follows:if two atomic ensembles are put into the optomechanical system,the strong mechanical squeezing beyond 3 dB is achieved even in the highly unresolved sideband regime;the steady state entanglement between the cavity and mechanical resonator can also be obtained.