title: Observation of dynamical instability for a Bose-Einstein condensate in a moving 1D optical lattice.
abstract: 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.
authors.affiliation: LENS, Dipartimento di Fisica, and INFM, Università di Firenze, via Nello Carrara 1, I-50019 Sesto Fiorentino (FI), Italy. fallani@lens.unifi.it
authors.forename: L
authors.initials: L
authors.lastname: Fallani
authors.forename: L
authors.initials: L
authors.lastname: De Sarlo
authors.forename: J E
authors.initials: JE
authors.lastname: Lye
authors.forename: M
authors.initials: M
authors.lastname: Modugno
authors.forename: R
authors.initials: R
authors.lastname: Saers
authors.forename: C
authors.initials: C
authors.lastname: Fort
authors.forename: M
authors.initials: M
authors.lastname: Inguscio