Broken cylindrical symmetry in binary mixtures of Bose-Einstein condensates

We provide Monte Carlo simulation and analytic interface arguments for the absence of cylindrical symmetry in the density difference of a binary mixtu re of Bose-Einstein condensates in traps in the phase segregated regime. Fo r different spin states of Rb-87, the total density remains very symmetric however. There is a metastable symmetric phase in a substantial part of thi s phase segregated regime. The boundary between the symmetric and the nonsy mmetric phase is a function of the relative concentration. The effect of di fferent confining potentials is investigated. [S1050-2947(99)01202-0].