title: Superfluidity versus Bloch oscillations in confined atomic gases.
abstract: We study the superfluid properties of (quasi) one-dimensional bosonic atom gases/liquids in traps with finite geometries in the presence of strong quantum fluctuations. Driving the condensate with a moving defect we find the nucleation rate for phase slips using instanton techniques. While phase slips are quenched in a ring resulting in a superfluid response, they proliferate in a tube geometry where we find Bloch oscillations in the chemical potential. These Bloch oscillations describe the individual tunneling of atoms through the defect and thus are a consequence of particle quantization.
authors.affiliation: Theoretische Physik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
authors.forename: H P
authors.initials: HP
authors.lastname: Büchler
authors.forename: V B
authors.initials: VB
authors.lastname: Geshkenbein
authors.forename: G
authors.initials: G
authors.lastname: Blatter