Bose-Einstein-condensate polaron in harmonic trap potentials in the weak-coupling regime: Lee-Low-Pines-type approach
Bose-Einstein-condensate polaron in harmonic trap potentials in the weak-coupling regime: Lee-Low-Pines-type approach
复制标题
弱耦合状态下谐波陷阱电位中的玻色-爱因斯坦凝聚极化子：Lee-Low-Pines 型方法
DOI：
10.1103/physreva.95.023626
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发表时间：
2017
影响因子：
2.9
通讯作者：
Kei Iida
中科院分区：
文献类型：
--
作者：
Eiji Nakano;Hiroyuki Yabu;Kei Iida
计算了超冷原子玻色-爱因斯坦凝聚体中单个杂质原子的零温结合能。杂质和凝聚态原子被困在各自的轴对称谐波势中，杂质通过低能波散射与凝聚态中的玻色子原子相互作用。在这种情况下，玻色子在杂质周围被激发，形成准粒子，即BEC极化子。我们发展了一种变分方法，即LaLee-Low-Pines（LLP）方法，用来描述绕对称轴具有守恒角动量的极化子。从数值结果中我们发现，杂质与激发玻色子之间的束缚打破了杂质能量相对于极化子总角动量的简并性。角动量部分地由激发玻色子以类似于在电子-声子系统的LLP理论中声子云对极化子动量的拖曳效应的方式共享。
We have calculated the zero-temperature binding energy of a single impurity atom immersed in a Bose-Einstein condensate (BEC) of ultracold atoms. The impurity and the condensed atoms are trapped in the respective axially symmetric harmonic potentials, where the impurity interacts with bosonic atoms in the condensate via low-energy-wave scattering. In this case, bosons are excited around the impurity to form a quasiparticle, namely, a BEC polaron. We have developed a variational method,a laLee-Low-Pines (LLP), for description of the polaron that has a conserved angular momentum around the symmetric axis. We find from numerical results that the binding between the impurity and the excited bosons breaks the degeneracy of the impurity energy with respect to the total angular momentum of the polaron. The angular momentum is partially shared by the excited bosons in a manner that is similar to the drag effect on the polaron momentum by a phonon cloud in the LLP theory for the electron-phonon system.