Ground state of the polaron in an ultracold dipolar Fermi gas
Ground state of the polaron in an ultracold dipolar Fermi gas
复制标题
DOI：
10.1103/physreva.103.033324
复制
发表时间：
2020-10
期刊：
影响因子：
--
通讯作者：
Kazuya Nishimura;E. Nakano;K. Iida;H. Tajima;T. Miyakawa;H. Yabu
中科院分区：
文献类型：
--
作者：
Kazuya Nishimura;E. Nakano;K. Iida;H. Tajima;T. Miyakawa;H. Yabu
由于杂质-费米相互作用，浸入超冷原子费米气体中的杂质原子可以形成准粒子，即所谓的费米极化子。我们考虑三维均匀偶极费米气体，其中原子间偶极相互作用(DDI)使费米表面形变为球状，用Chevy型变分方法研究了费米极化子的基态性质：有效质量、粒子-空穴(p-h)激发的动量分布、阻力参数和杂质周围的介质密度修正。这些量表现出空间各向异性，反映了背景偶极费米气体的动量各向异性。在杂质和费米子质量相等的情况下，我们还给出了杂质-费米子相互作用么正极限下极化子性质的数值结果。结果表明，当DDI强度从0美元增加到临界值附近时，极化子的横向有效质量和横向动量阻力参数都有减小的趋势，而纵向有效质量和横向动量阻力参数对DDI的依赖性很小。
An impurity atom immersed in an ultracold atomic Fermi gas can form a quasiparticle, so-called Fermi polaron, due to impurity-fermion interaction. We consider a three-dimensional homogeneous dipolar Fermi gas as a medium, where the interatomic dipole-dipole interaction (DDI) makes the Fermi surface deformed into a spheroidal shape, and, using a Chevy-type variational method, investigate the ground-state properties of the Fermi polaron: the effective mass, the momentum distribution of a particle-hole (p-h) excitation, the drag parameter, and the medium density modification around the impurity. These quantities are shown to exhibit spatial anisotropies in such a way as to reflect the momentum anisotropy of the background dipolar Fermi gas. We have also given numerical results for the polaron properties at the unitarity limit of the impurity-fermion interaction in the case in which the impurity and fermion masses are equal. It has been found that the transverse effective mass and the transverse momentum drag parameter of the polaron both tend to decrease by $ \sim 10\%$ when the DDI strength is raised from $0$ up to around its critical value, while the longitudinal ones exhibit a very weak dependence on the DDI.