Transition to Instability in a Kicked Bose-Einstein Condensate

The quantum dynamics of Bose-Einstein condensate (BEC) with repulsive interaction, that was confined on a ring and kicked periodically, was discussed. It was found that for weak interactions between atoms, periodic motion (antiresonance) becomes quasiperiodic (qantum beating) but remained stable. It was observed that there existed a critical strength of interactions beyond which quasiperiodic motion became chaotic, resulting in an instability of the condensate. Analysis shows that strong interactions (g = 5) destroys the quasiperiodic motion and leads to diffusive growth of energy.