title: Spin relaxation and band excitation of a dipolar Bose-Einstein condensate in 2D optical lattices.
abstract: We observe interband transitions mediated by dipole-dipole interactions for an array of 1D quantum gases of chromium atoms, trapped in a 2D optical lattice. Interband transitions occur when dipolar relaxation releases an energy larger than the lattice band gap. For symmetric lattice sites, and a magnetic field parallel to the lattice axis, we compare the measured dipolar relaxation rate with a Fermi golden rule calculation. Below a magnetic field threshold, we obtain an almost complete suppression of dipolar relaxation, leading to metastable 1D gases in the highest Zeeman state.
authors.affiliation: Laboratoire de Physique des Lasers, CNRS UMR 7538, Université Paris 13, 99 Avenue J.-B. Clément, 93430 Villetaneuse, France.
authors.forename: B
authors.initials: B
authors.lastname: Pasquiou
authors.forename: G
authors.initials: G
authors.lastname: Bismut
authors.forename: E
authors.initials: E
authors.lastname: Maréchal
authors.forename: P
authors.initials: P
authors.lastname: Pedri
authors.forename: L
authors.initials: L
authors.lastname: Vernac
authors.forename: O
authors.initials: O
authors.lastname: Gorceix
authors.forename: B
authors.initials: B
authors.lastname: Laburthe-Tolra