Spin excitations in a Fermi gas of atoms

Spin excitation in a quantum degenerate Fermi gas of atoms was experimentally investigated. The damping time of the collective excitation in the hydrodynamics regime was used to probe the interplay between interactions and quantum statistics in a Fermi gas of atoms. The excitation damping time was found to be reduced by factor of 2 at temperatures below the Fermi temperature compared to the classical excitation. A strong energy dependence on excitation energy was observed for the quantum statistical effect.