Stability and structure of an anisotropically trapped dipolar Bose-Einstein condensate: Angular and linear rotons
Stability and structure of an anisotropically trapped dipolar Bose-Einstein condensate: Angular and linear rotons
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DOI：
10.1103/physreva.86.053623
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发表时间：
2012-11-26
影响因子：
2.9
通讯作者：
Blakie, P. B.
中科院分区：
文献类型：
--
作者：
Martin, A. D.;Blakie, P. B.
我们从理论上研究了各向异性陷阱中具有极化偶极相互作用的玻色-爱因斯坦凝聚体。我们通过改变陷阱频率和偶极相互作用强度来映射参数空间，并发现参数空间中出现密度振荡凝聚态的不规则区域，最大密度远离陷阱中心。这些密度振荡状态可以是双凹的(红血球形状)，或者具有两个或四个峰。对于所有的陷阱频率，当偶极相互作用强度足够大时，凝聚体变得不稳定而不能崩塌。崩塌与元素激发的软化不谋而合。当凝聚态为密度振荡时，软化激发的性质与凝聚态的结构有关。我们根据线性和角度特性对这些激发进行了分类。我们还找到了Gross-Pitaevskii方程的激发解，这些解总是不稳定的。
We study theoretically Bose-Einstein condensates with polarized dipolar interactions in anisotropic traps. We map the parameter space by varying the trap frequencies and dipolar interaction strengths and find an irregular-shaped region of parameter space in which density-oscillating condensate states occur, with maximum density away from the trap center. These density-oscillating states may be biconcave (red-blood-cell-shaped), or have two or four peaks. For all trap frequencies, the condensate becomes unstable to collapse for sufficiently large dipole interaction strength. The collapse coincides with the softening of an elementary excitation. When the condensate mode is density oscillating, the character of the softening excitation is related to the structure of the condensate. We classify these excitations by linear and angular characteristics. We also find excited solutions to the Gross-Pitaevskii equation, which are always unstable.