Evidence for a Bose-Einstein condensate in dilute Rb gas by absorption image in a quadrupole and Ioffe configuration trap

We report the realization of Bose-Einstein condensation (BEC) in dilute rubidium gas. The BEC was achieved in a quadrupole and Ioffe configuration trap. The number of condensed atoms is around 4 × 10⁴ in total 5 × 10⁵, and the transition temperature is 250 nK. We have studied the light scattering of the atom cloud and the condensate in a tightly confined magnetic trap. We show that it is possible to use the diffraction patterns in the near-resonant imaging of the trapped cold atomic samples to give the information of the BEC phase transition.