耗散环境下三原子之间稳定纠缠的量子反馈控制

研究利用基于量子跳跃的量子反馈控制来产生三个二能级原子之间稳定的纠缠.考虑三个二能级原子处于一个严重耗散的单模光腔中,分别讨论了反馈作用在一个原子上和反馈同时作用在三个原子上的情况.研究发现:当反馈作用在某个原子上时,基于量子跳跃的量子反馈能够保护另外两个原子的最大纠缠态.当反馈同时作用在三个原子上时,选择合适的参数可以得到两个基矢张开的无消相干子空间,并且利用量子轨迹蒙特卡罗波函数方法,得到一定初始条件下系统最终可以演化到这个子空间中三个原子之间的最大纠缠态.

Controlling the entanglement among three atoms by quantum-jump-based feedback

We consider a model consisting of three two-level atoms in a heavily damped cavity. We show that the quantum-jump-based feedback can be used to generate a steady entangled state of three atoms against decoherence. When the feedback acts on just one of the atoms, it can protect a maximally entangled state of other two atoms. When the feedback acts on three atoms, by choosing appropriate parameters we can obtain a decoherence-free subspace spanned by two vectors, and by using quantum trajectory Monte Carlo wave function method we find that the maximally entangled state of three atoms in this decoherence-free subspace can be obtained for some specific initial conditions.