Dynamics of a strongly interacting Fermi gas : The radial quadrupole mode
Dynamics of a strongly interacting Fermi gas : The radial quadrupole mode
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DOI：
10.1103/physreva.76.033610
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发表时间：
2007-04
影响因子：
2.9
通讯作者：
A. Altmeyer;S. Riedl;M. Wright;C. Kohstall;J. Denschlag;R. D. O. Physics;Center for High Energy Physics-Center-for-High-Energy-P
中科院分区：
文献类型：
--
作者：
A. Altmeyer;S. Riedl;M. Wright;C. Kohstall;J. Denschlag;R. D. O. Physics;Center for High Energy Physics-Center-for-High-Energy-P
本文报道了在超冷、强相互作用的费米气体中的基元表面模的测量结果。径向四极模式使我们能够探测从玻色-爱因斯坦凝聚（BEC）到巴丁-库珀-施里弗（BCS）制度的交叉中的流体动力学行为，而不受状态方程变化的影响。我们研究了这种模式的频率和阻尼，沿着其扩展动力学。在么正性极限和共振的BEC侧，所观察到的频率与标准流体动力学理论一致。然而，在交叉的BCS侧，在流体动力学制度中观察到振荡频率的显著下移，作为突然过渡到无碰撞行为的前兆;这表明振荡与费米子对的耦合。
We report on measurements of an elementary surface mode in an ultracold, strongly interacting Fermi gas of $^{6}\mathrm{Li}$ atoms. The radial quadrupole mode allows us to probe hydrodynamic behavior in the crossover from Bose-Einstein condensation (BEC) to the Bardeen-Cooper-Schrieffer (BCS) regime without being influenced by changes in the equation of state. We examine the frequency and damping of this mode, along with its expansion dynamics. In the unitarity limit and on the BEC side of the resonance, the observed frequencies agree with standard hydrodynamic theory. However, on the BCS side of the crossover, a striking downshift of the oscillation frequency is observed in the hydrodynamic regime as a precursor to an abrupt transition to collisionless behavior; this indicates coupling of the oscillation to fermionic pairs.