双组分玻色-爱因斯坦浓度涡旋格子的 Tkachenko 模态与结构相变
摘要
我们考虑包含涡旋格子的快速旋转的双组分玻色-爱因斯坦浓度 (BEC)。在均场量子霍尔 regime 下，我们计算涡旋位置小振动（Tkachenko 模态）的色散关系，并考虑这些模态与密度激发的耦合。使用涡旋格子的解析密度形式，我们数值计算不同格子几何的弹性常数。我们还将此方法应用于计算单组分三角形格子的弹性常数。对于双组分 BEC，存在两种 Tkachenko 模态，分别称为声学模态和光学模态，类似于声子。对于所有格子类型，声学 Tkachenko 模态频率在长波数下呈二次波数依赖，而光学 Tkachenko 模态呈线性依赖。对于三角形格子，Tkachenko 模态的色散呈各向同性，而对于其他格子类型，色散关系表现出与格子对称性一致的各向异性。 Depending on the intercomponent interaction there are five distinct lattice types, and four structural phase transitions between them. Two of these transitions are second-order and are accompanied by the softening of an acoustic Tkachenko mode. The remaining two transitions are first-order and while one of them is accompanied by the softening of an optical mode, the other does not have any dramatic effect on the Tkachenko spectrum. We also find an instability of the vortex lattice when the intercomponent repulsion becomes stronger than the repulsion within components.
引用
@article{arxiv.cond-mat/0511512,
title = {Tkachenko modes and structural phase transitions of the vortex lattice of a two component Bose-Einstein condensate},
author = {M. Keceli and M. O. Oktel},
journal= {arXiv preprint arXiv:cond-mat/0511512},
year = {2007}
}
备注
24 pages, 13 figures, typos corrected, references added, final version