Fluid-dynamical scheme for equilibrium properties of two trapped fermion species with pairing interactions

P. CAPUZZI; E. S. HERNÁNDEZ; L. SZYBISZ

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

Año: 2008 vol. 78 p. 43619 - 4361910

1050-2947

   We present a generalization of the fluid-dynamical scheme developed for nuclear physics to the case of twotrapped fermion species with pairing interactions. To establish a macroscopic description of the mass andmomentum conservation laws, we adopt a generalization of the usual Thomas-Fermi approach that includes thepairing energy. We analyze the equilibrium density and gap profiles for an equal population mixture ofharmonically trapped 6Li atoms for different choices of the local equation of state. We examine slight depar-tures from equilibrium within our formulation, finding that density oscillations can propagate as first soundcoupled to pairing vibrations, that in a homogeneous fermion system exhibit a Bogoliubov-like quasiparticlespectrum. In this case, the dispersion relation for the coupled modes displays a rich scenario of stable, unstable,and damped regimes.