Breathing Oscillations and Quasi-Low-Dimensional Structures of Weakly-Interactins Degenerate Fermi Gases in Highly-Anisotropic Traps
Breathing Oscillations and Quasi-Low-Dimensional Structures of Weakly-Interactins Degenerate Fermi Gases in Highly-Anisotropic Traps
复制标题
高各向异性陷阱中弱相互作用简并费米气体的呼吸振荡和准低维结构
DOI：
10.1143/jpsj.81.044001
复制
发表时间：
2012
影响因子：
1.7
通讯作者：
T.Maruyama
中科院分区：
文献类型：
--
作者：
T.Nishimura;T.Maruyama
从理论上研究了强各向异性谐振子阱中弱相互作用简并费米气体的呼吸振荡。如果陷阱不是高度各向异性的，费米子表现为三维（3D）气体，并表现出耦合呼吸振荡，如在以前的论文中研究的[Phys. Rev. A75（2007）033611];否则费米子表现出准低维（QLD）性质，来自其单粒子谱中的特定结构，称为QLD结构。本文主要研究量子阱结构对具有对称布居数密度的双组分费米子呼吸振荡的影响。在这里，我们将半经典的Escheras-Fermi近似推广到高度各向异性系统，并在求和规则标度方法和微扰理论中获得集体频率。结果表明，在一阶微扰下，QLD结构的影响在横模中看不到，而只出现在具有反映QLD结构的层次结构的纵模中.我们还证明了在本框架中的振荡的时间演化。
We theoretically investigate breathing oscillations of weakly-interacting degenerate Fermi gases in highly-anisotropic harmonic oscillator traps. If the traps are not highly anisotropic, the fermions behave as three-dimensional (3D) gases and exhibit the coupled breathing oscillations as studied in a previous paper [Phys. Rev. A75(2007) 033611]; Otherwise the fermions exhibit quasi-low-dimensional (QLD) properties derived from specific structures in their single-particle spectrum, calledQLD structures. In the present paper, we focus on effects of the QLD structures on the breathing oscillations of the two-component fermions with symmetric population densities. Here we develop the semi-classical Thomas–Fermi approximation extended to the highly-anisotropic systems and obtain the collective frequencies in the sum-rule-scaling method and perturbation theory. As a result, we reveal that the effects of the QLD structures can not be seen in the transverse modes in the first-order perturbation and appear only in the longitudinal modes with hierarchies reflecting the QLD structures. We also demonstrate time-evolution of the oscillations in the present framework.