Experimental investigation of interactions between ultracold atoms and room-temperature surfaces

Yutaka Kobayashi

A. L. Marchant, S Händel, T P Wiles +2 more

We report on the guided transport of an atomic sample along an optical waveguide up to a room-temperature dielectric surface. The technique exploits a simple hybrid trap consisting of a single beam dipole trap positioned ∼125 μ m below the field zero of a magnetic quadrupole potential. Transportation is realized by applying a moderate bias field (<12 G) to displace the magnetic field zero of the quadrupole potential along the axis of the dipole trap. We use the technique to demonstrate that atomic gases may be controllably transported over 8 mm with negligible heating or loss. The transport path is completely defined by the optical waveguide and we demonstrate that, by aligning the waveguide through a super polished prism, ultracold atoms may be controllably delivered up to a predetermined region of a surface.

S. Händel, A. L. Marchant, Timothy P. Wiles +2 more

We present an apparatus designed for studies of atom-surface interactions using quantum degenerate gases of (85)Rb and (87)Rb in the vicinity of a room temperature dielectric surface. The surface to be investigated is a super-polished face of a glass Dove prism mounted in a glass cell under ultra-high vacuum. To maintain excellent optical access to the region surrounding the surface, magnetic transport is used to deliver ultracold atoms from a separate vacuum chamber housing the magneto-optical trap (MOT). We present a detailed description of the vacuum apparatus highlighting the novel design features; a low profile MOT chamber and the inclusion of an obstacle in the transport path. We report the characterization and optimization of the magnetic transport around the obstacle, achieving transport efficiencies of 70% with negligible heating. Finally, we demonstrate the loading of a hybrid optical-magnetic trap with (87)Rb and the creation of Bose-Einstein condensates via forced evaporative cooling close to the dielectric surface.

Svetlana Kotochigova

Mukund Vengalattore, Wilbert Rooijakkers, Richard Conroy +1 more

Sebastian Kraft, A G nther, Herwig Ott +3 more

We have used ultracold atoms to characterize the magnetic field near the surface of copper conductors at room temperature carrying currents between 0.045 and 2 A. In addition to the usual circular field we find an additional, 1000–10 000 times smaller longitudinal field. The field changes its strength periodically with a period of 200–300 μ m.