Observation of spinor dynamics in optically trapped 87Rb Bose-Einstein condensates.

We measure spin mixing of F=1 and F=2 spinor condensates of 87Rb atoms confined in an optical trap. We determine the spin mixing time to be typically less than 600 ms and observe spin population oscillations. The equilibrium spin configuration in the F=1 manifold is measured for different magnetic fields and found to show ferromagnetic behavior for low field gradients. An F=2 condensate is created by microwave excitation from the F=1 manifold, and this spin-2 condensate is observed to decay exponentially with time constant 250 ms. Despite the short lifetime in the F=2 manifold, spin mixing of the condensate is observed within 50 ms.

[The tracheostomy-sphincter procedure - case report of a modified tracheostomy]. / Der Tracheostomasphinkter - Kasuistik einer modifizierten Methode zur Tracheostomaanlage -

BACKGROUND: For an adequate speech production after tracheostomy patients are dependant on a temporary closure of the stoma. This closure can either be done manually or by the use of various tracheostoma valves. The tracheostomy-sphincter procedure, which is introduced in this case, allows the voluntary constriction of the stoma. METHODS: This case describes the treatment of a paediatric patient with laryngeal stenosis. During tracheostomy formation, an artificial muscle-sphincter was created, using the sternohyoid muscle (strap muscle). RESULTS: Postoperative contractile movements were possible, which were improved by special exercises. After 3 months the complete closure of the tracheostoma was achieved. CONCLUSIONS: The establishment of a tracheostomy-sphincter can be carried out during tracheostomy and allows the patient to speak without the use of a device. Tracheobronchial secretions can be cleared via the pharynx by coughing.

All-optical formation of an atomic Bose-Einstein condensate.

We have created a Bose-Einstein condensate (BEC) of 87Rb atoms directly in an optical trap. We employ a quasielectrostatic dipole force trap formed by two crossed CO2 laser beams. Loading directly from a sub-Doppler laser-cooled cloud of atoms results in initial phase space densities of approximately 1/200. Evaporatively cooling through the BEC transition is achieved by lowering the power in the trapping beams over approximately 2 s. The resulting condensates are F = 1 spinors with 3.5x10(4) atoms distributed between the m(F) = (-1,0,1) states.

Storage ring for neutral atoms.

We have demonstrated a storage ring for ultracold neutral atoms. Atoms with mean velocities of 1 m/s corresponding to kinetic energies of approximately 100 neV are confined to a 2 cm diameter ring by magnetic forces produced by two current-carrying wires. Up to 10(6) atoms are loaded at a time in the ring, and seven revolutions are clearly observed. Additionally, we have demonstrated multiple loading of the ring and deterministic manipulation of the longitudinal velocity distribution of the atoms using applied laser pulses. Applications of this ring include large area atom interferometers and monochromatic atomic beam generation.