In spite of the important differences in
typical energy and size scales, many analogies exist between nuclei and
ultra-cold gases of trapped atoms.
In the last decade, experiments studying dilute gases of electrically neutral atoms in artificial optical or magneto-optical potentials
made tremendous progress. In the case of fermionic atoms in a trap, the
close analogy between these systems and nuclei where nucleons move in
the mean field is evident. Many concepts of nuclear physics, such as
pairing and collective modes, have also been studied in cold atoms, and a
fruitful exchange between the two fields has developed. Recently, we
were mainly interested in the transition from the hydrodynamic to the
collisionless regime, as the temperature of the gas increases, the gas
expands, and the collision rate of the atoms decreases. Good agreement
with the experimentally measured frequencies and damping rates of
quadrupole and dipole modes was obtained.
Another subject studied by the group is
atoms with magnetic dipole-dipole interactions. This topic is very
timely since the first degenerate dipolar Fermi gas was created only
very recently. The dipole-dipole interaction is also interesting from
the nuclear physics point of view, since it is very similar to the
tensor force between nucleons. We have shown that in the case of dipolar
atoms, a new instability of the Hartree-Fock ground state with a
spherical Fermi surface can appear, which leads to the formation of a
spin texture in momentum space.