Controlling phase separation of binary Bose-Einstein condensates via mixed-spin-channel Feshbach resonance

We investigate controlled phase separation of a binary Bose-Einstein condensate in the proximity of a mixed-spin-channel Feshbach resonance in the vertical bar F = 1, m(F) = +1 > and vertical bar F = 2, mF = -1 > states of Rb-87 at a magnetic field of 9.10 G. Phase separation occurs on the lower-magnetic-field side of the Feshbach resonance while the two components overlap on the higher-magnetic-field side. The Feshbach resonance curve of the scattering length is obtained from the shape of the atomic cloud by comparison with the numerical analysis of coupled Gross-Pitaevskii equations.