Propagation of second sound in a superfluid Fermi gas in the unitary limit
Propagation of second sound in a superfluid Fermi gas in the unitary limit
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DOI：
10.1103/physreva.80.043613
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发表时间：
2009-10-01
影响因子：
2.9
通讯作者：
Nikuni, Tetsuro
中科院分区：
文献类型：
--
作者：
Arahata, Emiko;Nikuni, Tetsuro
研究了在么正极限下，费米原子组成的均匀超流气体中的声传播。正常和超流分量的存在导致出现两个声音模式的碰撞制度，称为第一和第二声音。第二种声音特别令人感兴趣，因为它是超流体成分的清晰信号。利用朗道的双流体流体力学理论，我们计算了流体力学声速和密度响应函数中的这些权重。后者用于计算对产生脉冲传播的外部电势的突然修改的响应。脉冲的幅度是成比例的响应函数中的权重计算，的基础上的方法的Noziegraveres和Schmitt-Rink的BCS-BEC。研究表明，在幺正性的超流费米气体中，第二声脉冲被密度扰动激发出一个很好的振幅。
We study sound propagation in a uniform superfluid gas of Fermi atoms in the unitary limit. The existence of normal and superfluid components leads to appearance of two sound modes in the collisional regime, referred to as first and second sounds. The second sound is of particular interest as it is a clear signal of a superfluid component. Using Landau's two-fluid hydrodynamic theory, we calculate hydrodynamic sound velocities and these weights in the density response function. The latter is used to calculate the response to a sudden modification of the external potential generating pulse propagation. The amplitude of a pulse which is proportional to the weight in the response function is calculated, the basis of the approach of Noziegraveres and Schmitt-Rink for the BCS-BEC. We show that, in a superfluid Fermi gas at unitarity, the second-sound pulse is excited with an appreciate amplitude by density perturbations.