Calculation of Drag and Superfluid Velocity from the Microscopic Parameters and Excitation Energies of a Two-Component Bose-Einstein Condensate on an Optical Lattice
Calculation of Drag and Superfluid Velocity from the Microscopic Parameters and Excitation Energies of a Two-Component Bose-Einstein Condensate on an Optical Lattice
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根据光学晶格上二元玻色-爱因斯坦凝聚体的微观参数和激发能计算阻力和超流体速度
DOI：
10.1103/physreva.79.063610
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
A. Sudbø
中科院分区：
文献类型：
--
作者：
J. Linder;A. Sudbø
我们研究了驻留在光学晶格上的两组分玻色-爱因斯坦凝聚体的模型。在平均场水平下的Bogolioubov近似下，我们得到了考虑跃迁和任意位置相互作用时双组分凝聚态激发谱的精确解析表达式。因此，我们的结果构成了试图阐明系统中高阶相互作用的影响的工作的基础。对于两种特殊相关的极限情况，我们更详细地研究了激发谱和超流速度的两个分支。此外，我们还将有效玻色-哈伯德模型中的跳跃和相互作用参数与系统中的微观参数联系起来，例如凝聚体中各组分的激光波长和原子质量。这些结果随后被用来解析和数值计算凝析油各组分之间的阻力系数。我们发现，无论组元间相互作用的强度和晶格势垒深度有多大，在接近组分质量相等的对称情况下，阻力是最有效的。
We investigate a model of a two-component Bose-Einstein condensate residing on an optical lattice. Within a Bogolioubov-approach at the mean-field level, we derive exact analytical expressions for the excitation spectrum of the two-component condensate when taking into account hopping and interactions between arbitrary sites. Our results thus constitute a basis for works that seek to clarify the effects of higher-order interactions in the system. We investigate the excitation spectrum and the two branches of superfluid velocity in more detail for two limiting cases of particular relevance. Moreover, we relate the hopping and interaction parameters in the effective Bose-Hubbard model to microscopic parameters in the system, such as the laserlight wavelength and atomic masses of the components in the condensate. These results are then used to calculate analytically and numerically the drag coefficient between the components of the condensate. We find that the drag is most effective close to the symmetric case of equal masses between the components, regardless of the strength of the intercomponent interaction and the lattice well depth.