We propose a scheme to control quantum coherence of a two-component Bose–Einstein condensate (BEC) by a single impurity atom immersed in the BEC. We show that the single impurity atom can act as a single-atom valve (SAV) to control quantum coherence of the two-component BEC. It is demonstrated that the SAV can realize the on-demand control over quantum coherence at an arbitrary time. Specially, it is found that the SAV can also control higher-order quantum coherence of two-component BEC. We investigate the long-time evolution of quantum coherence of the two-component BEC and find that collapse–revival patterns of quantum coherence can be manipulated by the initial-state parameters of the impurity atom and the impurity–BEC interaction strengths.

中文翻译：

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通过杂质原子控制两组分玻色-爱因斯坦凝聚物的量子相干性

我们提出了一种通过浸入BEC中的单个杂质原子来控制两组分玻色-爱因斯坦凝聚物（BEC）的量子相干性的方案。我们表明，单个杂质原子可以充当单原子阀（SAV）来控制两组分BEC的量子相干性。证明了SAV可以在任意时间实现对量子相干的按需控制。特别地，发现SAV还可以控制两组分BEC的高阶量子相干性。我们研究了两组分BEC的量子相干性的长期演变，发现可以通过杂质原子的初始状态参数和杂质-BEC相互作用强度来控制量子相干性的崩溃-恢复模式。