标题： 超冷费米超流体中的极化子 显示英文标题

标题： Polarons in Ultracold Fermi Superfluids

摘要： 我们研究了一种由杂质与超冷费米超流体相互作用引起的新型费米极化子。 由于系统的三组分特性，极化子可以变得类似三聚体，并具有非普遍的能量谱。 我们在吸引性和排斥性极化子谱中都识别出杂质和类似三聚体的解之间的多个避让交叉。 特别是，避让交叉的宽度随着费米超流体从BCS侧向BEC侧的跃迁而逐渐增加，这表明向三体损失的不稳定性。 对于有效范围较小的相互作用势，这些损失可以减少。 我们还使用二阶微扰理论证明，即使对于小的费米子-杂质散射长度，费米子-杂质相互作用能的平均场评估也是不充分的，这是由于该系统中费米超流体和短程物理的本质效应。 我们的结果在混合物的冷原子实验中具有实际应用价值。 显示英文摘要

摘要： We study a new type of Fermi polaron induced by an impurity interacting with an ultracold Fermi superfluid. Due to the three-component nature of the system, the polaron can become trimer-like with a non-universal energy spectrum. We identify multiple avoided crossings between impurity- and trimer-like solutions in both the attractive and the repulsive polaron spectra. In particular, the widths of avoided crossings gradually increase as the Fermi superfluid undergoes a crossover from the BCS side towards the BEC side, which suggests instabilities towards three-body losses. Such losses can be reduced for interaction potentials with small effective ranges. We also demonstrate, using the second-order perturbation theory, that the mean-field evaluation of the fermion-impurity interaction energy is inadequate even for small fermion-impurity scattering lengths, due to the essential effects of Fermi superfluid and short-range physics in such a system. Our results are practically useful for cold atom experiments on mixtures.