574 research outputs found
Laser-driven Sisyphus cooling in an optical dipole trap
We propose a novel Sisyphus cooling scheme for atoms confined in a far off
resonance optical dipole trap. Utilizing the differential trap-induced AC Stark
shift, two electronic levels of the atom are resonantly coupled by a cooling
laser preferentially near the trap bottom. After absorption of a cooling
photon, the atom loses energy by climbing the steeper potential, and then
spontaneously decays preferentially away from the trap bottom. The proposed
method is particularly suited to cooling alkaline-earth-like atoms where
two-level systems with narrow electronic transitions are present. Numerical
simulations for the cases of Sr and Yb demonstrate the expected
recoil and Doppler temperature limits. The method requires a relatively small
number of scattered photons and can potentially lead to phase space densities
approaching quantum degeneracy in sub-second timescales.Comment: 9 pages, 8 figure
Atomic Interactions in Precision Interferometry Using Bose-Einstein Condensates
We present theoretical tools for predicting and reducing the effects of
atomic interactions in Bose-Einstein condensate (BEC) interferometry
experiments. To address mean-field shifts during free propagation, we derive a
robust scaling solution that reduces the three-dimensional Gross-Pitaevskii
equation to a set of three simple differential equations valid for any
interaction strength. To model the other common components of a BEC
interferometer---condensate splitting, manipulation, and recombination---we
generalize the slowly-varying envelope reduction, providing both analytic
handles and dramatically improved simulations. Applying these tools to a BEC
interferometer to measure the fine structure constant (Gupta, et al., 2002), we
find agreement with the results of the original experiment and demonstrate that
atomic interactions do not preclude measurement to better than part-per-billion
accuracy, even for atomic species with relatively large scattering lengths.
These tools help make BEC interferometry a viable choice for a broad class of
precision measurements.Comment: 8 pages, 6 figures, revised based on reviewer comment
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