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BEC observed at the University of Texas

[Historical report created from GSU BEC Homepage:]

"A new experiment demonstrating BEC of 87Rb in a TOP trap was reported today by a group at the University of Texas at Austin.

Speaking at the CLEO/QELS '97 Conference, Dr. Dian-Juin Han showed observations of a BEC containing approximately 20,000 atoms in a time-averaged orbiting potential (TOP) trap similar to that previously used at JILA. Co-authors on the paper were Roahn Wynar, Philippe Courteille, and Dan Heinzen.

The Texas team used a Zeeman slower to load approximately 5x109 atoms of 87Rb (in the |F MF> = |2 2> hyperfine state) into a magneto-optical trap (MOT), where the atoms were cooled to 70 µK in optical molasses. After laser cooling, the MOT was turned off and the TOP trap was activated. RF evaporative cooling was then performed, reaching temperatures below 30 nK. The final TOP trap configuration had a radial frequency of 18 Hz. The trap was then released, and velocity-space images of the BEC were acquired by real-space photography of the expanding gas, along the lines described by Cornell. The observations show the characteristic anisotropic BEC peak superposed upon the isotropic thermal pedestal. The transition temperature for this system as predicted by ideal gas theory is 31 nK. At the lowest temperatures attained, approximately 20,000 atoms were contained in the condensate peak.

Further information on this experiment is available at the group's Web site."