Trap anharmonicity and sloshing mode of a Fermi gas
Résumé
For a gas trapped in a harmonic potential, the sloshing (or Kohn) mode is undamped and its frequency coincides with the trap frequency, independently of the statistics, interaction and temperature of the gas. However, experimental trap potentials have usually Gaussian shape and anharmonicity effects appear as the temperature and, in the case of Fermions, the filling of the trap are increased. We study the sloshing mode of a degenerate Fermi gas in an anharmonic trap within the Boltzmann equation, including in-medium effects in both the transport and collision terms. We calculate the shift of the sloshing frequency due to the anharmonicity and the damping of the sloshing mode due to its coupling to more complicated transverse and bending modes.