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We have experimentally studied the unstable dynamics of a harmonically trapped Bose-Einstein condensate loaded into a 1D moving optical lattice. The lifetime of the condensate in such a potential exhibits a dramatic dependence on the quasimomentum state. This is unambiguously attributed to the onset of dynamical instability, after a comparison with the predictions of the Gross-Pitaevskii theory. Deeply in the unstable region we observe the rapid appearance of complex structures in the atomic density profile, as a consequence of the condensate phase uniformity breakdown. L. Fallani et al. |
In June 10th 1999, the Rubidium BEC1 apparatus produced the first italian Bose-Einstein condensate. We soon focused our activity on the study of a quantum gas of 87Rb bosons in optical lattices, investigating static and dynamic properties and enlightening the role of different kinds of instabilities. The last part of the activity was concentrated on the study of the superfluid to Mott insulator transition (also adding disorder and “quasi-disorder”) and on the physics of low-dimensional bosonic gases, characterized by measuring the excitation spectrum of these systems through inelastic light scattering. The BEC1 experiment retired in 2014 after 15 years of activity. We would like to thank all the people – students, technicians, and researchers – who have contributed to these exciting fifteen years of activity.