title: Klein tunneling of a quasirelativistic Bose-Einstein condensate in an optical lattice.
abstract: A proof-of-principle experiment simulating effects predicted by relativistic wave equations with ultracold atoms in a bichromatic optical lattice that allows for a tailoring of the dispersion relation is reported. We observe the analog of Klein tunneling, the penetration of relativistic particles through a potential barrier without the exponential damping that is characteristic for nonrelativistic quantum tunneling. Both linear (relativistic) and quadratic (nonrelativistic) dispersion relations are investigated, and significant barrier transmission is observed only for the relativistic case.
authors.affiliation: Institut für Angewandte Physik der Universität Bonn, Wegelerstr. 8, 53115 Bonn, Germany. salger@iap.uni-bonn.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Salger
authors.forename: Christopher
authors.initials: C
authors.lastname: Grossert
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kling
authors.forename: Martin
authors.initials: M
authors.lastname: Weitz