Beats and Expansion of Two-Component Bose-Einstein Condensates in the   Thomas-Fermi Limit
  A unique feature of multi-component BECs is the possibility of beating frequencies in collective oscillations. We analytically determine this beating frequency for the two-component BEC in one-dimension. We also show that the Thomas-Fermi approximation, where the quantum pressure is neglected, describes well the expansion of the two-component condensate released from an harmonic trap. 
James Q. Quach
cond-mat.quant-gas