Slowly moving matter--wave gap soliton propagation in weak random nonlinear potential
Zhang Ming-Rui(张铭锐)a)b)†, Zhang Yong-Liang(张永亮)b), Jiang Xun-Ya(蒋寻涯)b), and Zi Jian(资剑)a)
aSurface Physics Laboratory (National Key Lab), Fudan University, Shanghai 200433, China; bInstitute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
Abstract We systematically investigate the motion of slowly moving matter--wave gap solitons in a nonlinear potential, produced by the weak random spatial variation of the atomic scattering length. With the weak randomness, we construct an effective-particle theory to study the motion of gap solitons. Based on the effective-particle theory, the effect of the randomness on gap solitons is obtained, and the motion of gap solitons is finally solved. Moreover, the analytic results for the general behaviours of gap soliton motion, such as the ensemble-average speed and the reflection probability depending on the weak randomness are obtained. We find that with the increase of the random strength the ensemble-average speed of gap solitons decreases slowly where the reduction is proportional to the variance of the weak randomness, and the reflection probability becomes larger. The theoretical results are in good agreement with the numerical simulations based on the Gross--Pitaevskii equation.
Received: 15 May 2007
Revised: 25 December 2007
Accepted manuscript online:
PACS:
03.75.Lm
(Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations)
Fund: Project supported by the National
Basic Research Program of China (Grant No 2006CB921701-6), Pujiang
Talent Project (Grant No PJ2005(00593)), and the Hundred Tarent
Project of the Chinese Academy of Sciences, China.
Cite this article:
Zhang Ming-Rui(张铭锐), Zhang Yong-Liang(张永亮), Jiang Xun-Ya(蒋寻涯), and Zi Jian(资剑) Slowly moving matter--wave gap soliton propagation in weak random nonlinear potential 2008 Chin. Phys. B 17 2160
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