Abstract
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 with a magnetically tunable scattering length close to zero. For , as the cloud profiles evolve, the measured difference in the densities at the cloud center increases in 200 ms from 0 to of the initial mean density and changes sign with . 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 , long compared to the axial trapping period of 6.9 ms. We find the zero crossing in , where spin segregation ceases, at .
- Received 7 May 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.150401
©2008 American Physical Society
Viewpoint
Spinning fermions
Published 6 October 2008
Spin dependence of atomic and electronic interactions can give rise to propagating regions of aligned spins in solids called spin waves. These have now been observed in a gas of ultracold fermionic atoms.
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