Bose-Einstein condensation of rubidium-87 atoms in a magnetic trap

심우식

Dongfang, Zhang, Tianyou +7 more

Yoshio Torii

Experimental techniques to produce and observe a Bose-Einstein condensate of rubidium atoms are presented. The atoms are first optically cooled and trapped in an ultra-high vacuum (-10-11 torr) glass cell using a double magneto-optical trap, and then transferred to a “cloverleaf” magnetic trap. Rf-induced evaporation is performed to further cool the magnetically trapped atoms below the phase transition of Bose-Einstein condensation. The velocity distribution (inferred by absorption imaging) of the cooled atomic cloud clearly shows the expected bi-modal structure characteristic of a condensate

Seokchan Hong

Dongfang Zhang, Tianyou Gao, Lingran Kong +2 more

We experimentally produce the rubidium Bose—Einstein condensate in an optically plugged magnetic quadrupole trap. A far blue-detuned focused laser beam with a wavelength of 532 nm is plugged in the center of the magnetic quadrupole trap to increase the number of trapped atoms and to suppress the heating. An rf evaporative cooling in the magneto-optical hybrid trap is applied to decrease the atom temperature into degeneracy. The atom number of the condensate is 1.2(0.4) × 10 5 and the temperature is below 100 nK. We also study characteristic behaviors of the condensate, such as phase space density, condensate fraction and anisotropic expansion.

Jörg Helge Müller, D. Ciampini, O. Morsch +5 more

We report the results of experiments with Bose-Einstein condensates of rubidium atoms in a triaxial TOP trap, presenting measurements of the condensate fraction and the free expansion of a condensate released from the trap. The experimental apparatus and the methods used to calibrate the magnetic trapping fields are discussed in detail. Furthermore, we compare the performance of our apparatus with other TOP traps and discuss possible limiting factors for the size of condensates achievable in such traps.