title: Superfluid and dissipative dynamics of a Bose-Einstein condensate in a periodic optical potential.
abstract: We create Bose-Einstein condensates of 87Rb in a static magnetic trap with a superimposed blue-detuned 1D optical lattice. By displacing the magnetic trap center we are able to control the condensate evolution. We observe a change in the frequency of the center-of-mass oscillation in the harmonic trapping potential, in analogy with an increase in effective mass. For fluid velocities greater than a local speed of sound, we observe the onset of dissipative processes up to full removal of the superfluid component. A parallel simulation study visualizes the dynamics of the Bose-Einstein condensate and accounts for the main features of the observed behavior.
authors.affiliation: INFM-LENS, Dipartimento di Fisica, Università di Firenze, Largo Enrico Fermi 2, I-50125 Firenze, Italia.
authors.forename: S
authors.initials: S
authors.lastname: Burger
authors.forename: F S
authors.initials: FS
authors.lastname: Cataliotti
authors.forename: C
authors.initials: C
authors.lastname: Fort
authors.forename: F
authors.initials: F
authors.lastname: Minardi
authors.forename: M
authors.initials: M
authors.lastname: Inguscio
authors.forename: M L
authors.initials: ML
authors.lastname: Chiofalo
authors.forename: M P
authors.initials: MP
authors.lastname: Tosi