Atomic Bose-Einsteincondensation with three-body interactions and collective excitations

Abstract

The stability of a Bose-Einstein condensed state of trapped ultra-coldatomsis investigated under the assumption of an attractive two-body anda repulsive three-body interaction. The Ginzburg-Pitaevskii-Gross (GPG)nonlinear Schrödinger equation is extended to include an effectivepotential dependent on the square of the density and solved numericallyforthe s-wave. The lowest collective mode excitations are determinedand their dependences on the number of atoms and on the strength of thethree-body force are studied. The addition of three-body dynamicscan allow the number of condensed atoms to increase considerably, evenwhenthe strength of the three-body force is very small compared with thestrengthof the two-body force. We study in detail the first-order liquid-gas phasetransition for the condensed state, which can happen in a critical range ofthe effective three-body force parameter.