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arXiv 1709.00862cond-mat.quant-gas
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超流费米气体中的暗孤子碰撞

Dark soliton collisions in superfluid Fermi gases

Wout Van Alphen, Giovanni Lombardi, Sergei N. Klimin, Jacques Tempere

摘要:

本文利用最近发展起来的有限温度有效场论研究了一维超流费米气体中BEC-BCS渡越区的暗孤子碰撞[S. N. Klimin,J. Tempere,G. Lombardi,J. T.欧洲德弗里斯B 88,122(2015)]。基于该理论的对场非线性运动方程,数值模拟了两个反向传播孤子的演化过程。由此产生的碰撞被观察到引入到孤子的轨迹的空间移位。在不同的温度和自旋不平衡条件下,计算和研究了这种位移的大小。当远离BEC制度,碰撞被发现成为非弹性的,发射损失的能量的形式小振幅密度振荡。这种非弹性是量化的,其行为进行分析,并与其他作品的结果进行比较。计算了密度振荡的色散关系,并与超流的集体激发谱进行了比较。

英文摘要:

In this work dark soliton collisions in a one-dimensional superfluid Fermi gas are studied across the BEC-BCS crossover by means of a recently developed finite-temperature effective field theory [S. N. Klimin, J. Tempere, G. Lombardi, J. T. Devreese, Eur. Phys. J. B 88, 122 (2015)] . The evolution of two counter-propagating solitons is simulated numerically based on the theory's nonlinear equation of motion for the pair field. The resulting collisions are observed to introduce a spatial shift into the trajectories of the solitons. The magnitude of this shift is calculated and studied in different conditions of temperature and spin-imbalance. When moving away from the BEC-regime, the collisions are found to become inelastic, emitting the lost energy in the form of small-amplitude density oscillations. This inelasticity is quantified and its behavior analyzed and compared to the results of other works. The dispersion relation of the density oscillations is calculated and is demonstrated to show a good agreement with the spectrum of collective excitations of the superfluid.

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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