arXiv 1201.09562012-01cond-mat.quant-gasnlin.PS

准一维玻色-爱因斯坦凝聚体绕非线性势垒的流动

Quasi 1D Bose-Einstein condensate flow past a nonlinear barrier

F. Kh. Abdullaev, R. M. Galimzyanov, Kh. N. Ismatullaev

备注：: 6 pages, 7 figures, extended abstract, revised arguments in Sects 2,3 results unchanged, added references
DOI：: 10.1016/j.physleta.2012.09.004

摘要：

研究了准一维{ \it排斥} BEC流通过非线性障碍物的问题。两种类型的非线性障碍被认为是，广泛和短程的。利用流体动力学方法求解一维Gross-Pitaevskii方程，得到了BEC运动通过宽排斥势垒和临界速度的稳态解。结果表明，在线性障碍的情况下，对于一个广泛的{ \it非线性}障碍的速度间隔$0 < v < v_-$ { \it总是}存在，其中的流动是超流的势垒强度无关。对于$δ$功能的障碍的情况下，低于临界速度存在两个稳定的解决方案，稳定和不稳定的。一个不稳定的解决方案被证明衰减成一个灰孤子上游和一个稳定的解决方案。衰减伴随着色散冲击波在屏障前向下游传播。

英文摘要：

The problem of a quasi 1D {\it repulsive} BEC flow past through a nonlinear barrier is investigated. Two types of nonlinear barriers are considered, wide and short range ones. Steady state solutions for the BEC moving through a wide repulsive barrier and critical velocities have been found using hydrodynamical approach to the 1D Gross-Pitaevskii equation. It is shown that in contrast to the linear barrier case, for a wide {\it nonlinear} barrier an interval of velocities $0 < v < v_-$ {\it always} exists, where the flow is superfluid regardless of the barrier potential strength. For the case of the $δ$ function-like barrier, below a critical velocity two steady solutions exist, stable and unstable one. An unstable solution is shown to decay into a gray soliton moving upstream and a stable solution. The decay is accompanied by a dispersive shock wave propagating downstream in front of the barrier.

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摘要：

英文摘要：

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