First and second sound of a unitary Fermi gas in highly oblate harmonic traps
First and second sound of a unitary Fermi gas in highly oblate harmonic traps
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DOI：
10.1088/1367-2630/16/8/083023
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发表时间：
2014-08
影响因子：
3.3
通讯作者：
Hui Hu;P. Dyke;C. Vale;Xiaji Liu
中科院分区：
文献类型：
--
作者：
Hui Hu;P. Dyke;C. Vale;Xiaji Liu
本文从理论上研究了有限温度下囚禁在高扁谐势阱中的幺正费米气体的第一和第二声模。根据Stringari及其同事的想法（2010年物理学评论Lett。105 150402），我们认为，这些模式可以由简化的二维两流体流体动力学方程描述。两种可能的方案-声波传播和呼吸模式激发-被认为是。我们计算的声波速度和离散的声音模式频率，作为温度的函数。我们发现，在这两个方案中，第一和第二声模式之间的耦合是足够大的，以引起显着的密度波动，这表明第二声可以直接观察到通过测量原位密度分布。第二种声音呼吸模式的频率被发现是高度敏感的超流密度。
We theoretically investigate first and second sound modes of a unitary Fermi gas trapped in a highly oblate harmonic trap at finite temperatures. Following the idea by Stringari and co-workers (2010 Phys. Rev. Lett. 105 150402), we argue that these modes can be described by the simplified two-dimensional two-fluid hydrodynamic equations. Two possible schemes—sound wave propagation and breathing mode excitation—are considered. We calculate the sound wave velocities and discretized sound mode frequencies, as a function of temperature. We find that in both schemes, the coupling between first and second sound modes is large enough to induce significant density fluctuations, suggesting that second sound can be directly observed by measuring in situ density profiles. The frequency of the second sound breathing mode is found to be highly sensitive to the superfluid density.