Atomic Bose-Einstein condensation with three-body interactions and collective excitations

Abstract

The stability of a Bose-Einstein condensed state of trapped ultra-cold atoms is investigated under the assumption of an attractive two-body and a repulsive three-body interaction. The Ginzburg-Pitaevskii-Gross (GPG) nonlinear Schrödinger equation is extended to include an effective potential dependent on the square of the density and solved numerically for the s−wave. The lowest frequency of the collective mode is determined and its dependences on the number of atoms and on the strength of the three-body force are studied. We show that the addition of three-body dynamics can allow the number of condensed atoms to increase considerably, even when the strength of the three-body force is very small compared with the strength of the two-body force. We also observe a first-order liquid-gas phase transition for the condensed state up to a critical strength of the effective three-body force.PACS 03.75.Fi, 42.65.Sf, 36.40.Ei, 32.80.Pj

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