Department of Physics, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo 152-8551, Japan.
Phys Rev Lett. 2015 Mar 20;114(11):115302. doi: 10.1103/PhysRevLett.114.115302.
Recently it has been proposed that three-component Fermi gases may exhibit a new type of crossover physics in which an unpaired Fermi sea of atoms smoothly evolves into that of trimers in addition to the ordinary BCS-BEC crossover of condensed pairs. Here we study its corresponding polaron problem in which a single impurity atom of one component interacts with condensed pairs of the other two components with equal populations. By developing a variational approach in the vicinity of a narrow Feshbach resonance, we show that the impurity atom smoothly changes its character from atom to trimer with increasing the attraction and eventually there is a sharp transition to dimer. The emergent polaronic atom-trimer continuity can be probed in ultracold atoms experiments by measuring the impurity spectral function. Our novel crossover wave function properly incorporating the polaronic atom-trimer continuity will provide a useful basis to further investigate the phase diagram of three-component Fermi gases in more general situations.
最近有人提出，三组分费米气体可能会表现出一种新的交叉物理现象，其中除了普通的凝聚对 BCS-BEC 交叉之外，未配对的费米海原子还会平滑地演变成三聚体。在这里，我们研究了相应的极化子问题，其中一个组件的单个杂质原子与另外两个组件的凝聚对相互作用，其种群相等。通过在狭窄的费什巴赫共振附近发展变分方法，我们表明随着吸引力的增加，杂质原子会从原子平滑地转变为三聚体，最终会发生向二聚体的急剧转变。通过测量杂质谱函数，可以在超冷原子实验中探测到出极化子原子-三聚体连续性。我们新颖的交叉波函数适当包含了极化子原子-三聚体连续性，将为进一步研究更一般情况下的三组分费米气体的相图提供有用的基础。
