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arXiv 0807.3989cond-mat.other
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光晶格中玻色-爱因斯坦凝聚体的局域能隙孤子串

Localized gap soliton trains of Bose-Einstein condensates in an optical lattice

D. L. Wang, X. H. Yan, W. M. Liu

摘要:

本文发展了一种系统的分析方法来研究囚禁在光晶格中的准一维玻色-爱因斯坦凝聚体的线性和非线性孤波激发。对于线性情况,$nth$能带中的Bloch波是Mathieu函数$ce_{n-1}$和$se_n$的线性叠加;并且$nth$带隙中的Bloch波是$ce_n$和$se_n$的线性叠加。对于非线性情况,只有带隙内的孤子可能会产生,有两种类型的孤子-基本孤子(这是一个本地化的和稳定的状态)和次基本孤子(这是一个本地化的,但不稳定的状态)。此外,我们还发现通过调节晶格深度和间距,可以控制晶格中基孤子的钉扎位置和振幅。我们对基本孤子的数值计算结果与实验观测结果在定量上是一致的。{ \bf 92},230401(2004)]。此外,我们预测,在目前的实验条件下,可以通过增加凝聚体的长度来实现由多个基本孤子组成的局域间隙孤子训练。

英文摘要:

We develop a systematic analytical approach to study the linear and nonlinear solitary excitations of quasi-one-dimensional Bose-Einstein condensates trapped in an optical lattice. For the linear case, the Bloch wave in the $nth$ energy band is a linear superposition of Mathieu's functions $ce_{n-1}$ and $se_n$; and the Bloch wave in the $nth$ band gap is a linear superposition of $ce_n$ and $se_n$. For the nonlinear case, only solitons inside the band gaps are likely to be generated and there are two types of solitons -- fundamental solitons (which is a localized and stable state) and sub-fundamental solitons (which is a lacalized but unstable state). In addition, we find that the pinning position and the amplitude of the fundamental soliton in the lattice can be controlled by adjusting both the lattice depth and spacing. Our numerical results on fundamental solitons are in quantitative agreement with those of the experimental observation [Phys. Rev. Lett. {\bf92}, 230401 (2004)]. Furthermore, we predict that a localized gap soliton train consisting of several fundamental solitons can be realized by increasing the length of the condensate in currently experimental conditions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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