Stability of trapped ultracold Fermi gases using effective s- and p-wave contact interactions

The stability of trapped dilute Fermi gases against collapse towards large densities is studied. A Hermitian effective contact interaction for all par tial waves is derived, which is particularly suited for a mean-field descri ption of these systems. Including the s- and p-wave parts, explicit stabili ty conditions and critical particle numbers are given as a function of the scattering lengths. The p-wave contribution determines the stability of a s ingle-component gas and can substantially modify the stability of a two-com ponent gas. Moreover it may give rise to a novel p-wave stabilized high-den sity phase.