Phase separation and vortex states in the binary mixture of Bose-Einstein condensates

The phase separation and vortex states in a two-component Bose-Einstein con densate consisting of \F = 1, m(f) = -1] and \2, 1] internal spin states of Rb-87 atoms are considered in the framework of the Thomas-Fermi approximat ion. It is shown that in the nonrotating system, the atoms in the state par allel to1, -1 > form a shell around the atoms in the state \2, 1]. The crit ical angular velocity for each state is calculated. These velocities depend drastically on the relative concentrations of the components, the critical angular velocity of the outer component being less than the angular veloci ty of the inner one. It is shown that the atoms in the \1, -1] state can fo rm a rotating ring around the resting core of the atoms in the \2, 1] state . (C) 2000 MAIK "Nauka/Interperiodica".