Observation of anomalous spin segregation in a trapped Fermi gas.
Observation of anomalous spin segregation in a trapped Fermi gas.
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观察捕获的费米气体中的异常自旋偏析。
DOI：
10.1103/physrevlett.101.150401
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发表时间：
2008
影响因子：
8.6
通讯作者：
John E. Thomas
中科院分区：
文献类型：
--
作者：
X. Du;L. Luo;B. Clancy;John E. Thomas
我们报道了自旋偏析的观察，即两个自旋态的自旋密度分布随时间的分离，在一个被困的，相干制备的6Li的费米气体中，具有磁性可调的散射长度a12接近于零。当|a12|约= 5 bohr时，随着云廓线的演化，测量到的云中心密度差在200ms内从0增加到初始平均密度的约= 60%，并随a12变化符号。这些数据与费米气体的自旋波理论在振幅和时间演化上都不一致。相比之下，对于玻色气体，一个类似的理论已经成功地描述了先前观察到的自旋偏析。所观察到的分离原子密度分布远未达到平衡状态，但它们持续了约5秒，比轴向俘获期（6.9 ms）长。我们发现，在a12=0处，自旋偏析在527.5+/-0.2 G处停止。
We report the observation of spin segregation, i.e., time-dependent separation of the spin density profiles of two spin states, in a trapped, coherently prepared Fermi gas of 6Li with a magnetically tunable scattering length a12 close to zero. For |a12| approximately = 5 bohr, as the cloud profiles evolve, the measured difference in the densities at the cloud center increases in 200 ms from 0 to approximately = 60% of the initial mean density and changes sign with a12. The data are in disagreement in both amplitude and temporal evolution with a spin-wave theory for a Fermi gas. In contrast, for a Bose gas, an analogous theory has successfully described previous observations of spin segregation. The observed segregated atomic density profiles are far from equilibrium, yet they persist for approximately = 5 s, long compared to the axial trapping period of 6.9 ms. We find the zero crossing in a12=0, where spin segregation ceases, at 527.5+/-0.2 G.