HARTREE-FOCK THEORY FOR DOUBLE CONDENSATES

We present the first theoretical treatment that accounts in detail for a recent observation of overlapping Bose-Einstein condensates of two different Rb-87 hyperfine states [C.J. Myatt et al., Phys. Rev. Lett. 78, 586 (1997)]. Despite the complicated geometry, we have completed a three-dimensional Hartree-Fock calculation for the coupled condensate s. The calculation explains a number of its key properties: (i) The ma nner in which one condensate partially wraps around the other, (ii) th e mean separation between the two condensates including the effects of gravity and of their mutual interaction, and (iii) the surprisingly l ong lifetime of the trap.