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arXiv 0904.0995cond-mat.quant-gas
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准一维玻色-爱因斯坦凝聚体中超流临界速度以下杂质的拖曳力

Drag force on an impurity below the superfluid critical velocity in a quasi-one-dimensional Bose-Einstein condensate

Andrew G. Sykes, Matthew J. Davis, David C. Roberts

摘要:

在平均场Gross-Pitaevskii理论的背景下,在超流体中运动的障碍物在临界速度以下存在无摩擦流。我们计算了由于量子涨落和热涨落引起的次一阶修正,并发现在所有亚临界速度和温度下,δ函数杂质在准一维玻色-爱因斯坦凝聚体中运动时受到一个非零力的作用.这种力的产生是由于来自杂质两侧的反射量子涨落的多普勒频移的不平衡。我们的计算是基于一个一致的扩展Bogoliubov理论的相互作用强度的二阶,并找到新的解析解的Bogoliubov-de Gennes方程的灰孤子。我们的研究结果提出了关于量子动力学在超流体中形成持续电流的问题。

英文摘要:

The existence of frictionless flow below a critical velocity for obstacles moving in a superfluid is well established in the context of the mean-field Gross-Pitaevskii theory. We calculate the next order correction due to quantum and thermal fluctuations and find a non-zero force acting on a delta-function impurity moving through a quasi-one-dimensional Bose-Einstein condensate at all subcritical velocities and at all temperatures. The force occurs due to an imbalance in the Doppler shifts of reflected quantum fluctuations from either side of the impurity. Our calculation is based on a consistent extension of Bogoliubov theory to second order in the interaction strength, and finds new analytical solutions to the Bogoliubov-de Gennes equations for a gray soliton. Our results raise questions regarding the quantum dynamics in the formation of persistent currents in superfluids.

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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