Stabilization of a Bose-Einstein droplet by hyperfine Rabi oscillations

A self-trapped Bose-Einstein condensate is shown to be stabilized in two-dimensional free space by Rabi oscillations between two hyperfine states which make an effective interatomic interaction oscillate in time. The stabilization mechanism is elucidated by using a two-component Gross-Pitaevskii equation combined with a variational analysis. The parameter regime of stability is investigated.