title: Asymmetric Landau-Zener tunneling in a periodic potential.
abstract: Using a simple model for nonlinear Landau-Zener tunneling between two energy bands of a Bose-Einstein condensate in a periodic potential, we find that the tunneling rates for the two directions of tunneling are not the same. Tunneling from the ground state to the excited state is enhanced by the nonlinearity, whereas in the opposite direction it is suppressed. These findings are confirmed by numerical simulations of the condensate dynamics. Measuring the tunneling rates for a condensate of rubidium atoms in an optical lattice, we have found experimental evidence for this asymmetry.
authors.affiliation: INFM, Dipartimento di Fisica E. Fermi, Università di Pisa, Via Buonarroti 2, I-56127 Pisa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Jona-Lasinio
authors.forename: O
authors.initials: O
authors.lastname: Morsch
authors.forename: M
authors.initials: M
authors.lastname: Cristiani
authors.forename: N
authors.initials: N
authors.lastname: Malossi
authors.forename: J H
authors.initials: JH
authors.lastname: Müller
authors.forename: E
authors.initials: E
authors.lastname: Courtade
authors.forename: M
authors.initials: M
authors.lastname: Anderlini
authors.forename: E
authors.initials: E
authors.lastname: Arimondo