Superfluidity versus Bloch oscillations in confined atomic gases - art. no. 100403

We study the superfluid properties of (quasi) one-dimensional bosonic atom gases/liquids in traps with finite geometries in the presence of strong qua ntum fluctuations. Driving the condensate with a moving defect we find the nucleation rate for phase slips using instanton techniques. While phase sli ps are quenched in a ring resulting in a superfluid response, they prolifer ate in a tube geometry where we find Bloch oscillations in the chemical pot ential. These Bloch oscillations describe the individual tunneling of atoms through the defect and thus are a consequence of particle quantization.