Structure of binary Bose-Einstein condensates

Abstract

We identify all possible classes of solutions for two-component Bose-Einstein condensates (BECs) within the Thomas-Fermi (TF) approximation, and check these results against numerical simulations of the coupled Gross-Pitaevskii equations (GPEs). We find that they can be divided into two general categories. The first class contains solutions with a region of overlap between the components. The other class consists of non-overlapping wavefunctions, and contains also solutions that do not possess the symmetry of the trap. The chemical potential and average energy can be found for both classes within the TF approximation by solving a set of coupled algebraic equations representing the normalization conditions for each component. A ground state minimizing the energy (within both classes of the states) is found for a given set of parameters characterizing the scattering length and confining potential. In the TF approximation, the ground state always shares the symmetry of the trap. However, a full numerical solution of the coupled GPEs, incorporating the kinetic energy of the BEC atoms, can sometimes select a broken-symmetry state as the ground state of the system. We also investigate effects of finite-range interactions on the structure of the ground state.

Dual-species Bose-Einstein condensate ofRb87andCs133McCarron1, Cho2, Jenkin3 et al. 2011Phys. Rev. A248122680View full textAdd to dashboardCite

“…4). Qualitatively, these observations are strikingly similar to the symmetric and asymmetric structures predicted for an immiscible binary condensate based upon numerical simulations of two coupled Gross-Pitaevskii equations [41]. Experimentally, the structures are correlated with the number of atoms in each condensate.…”

Vortex sheet in rotating two-component Bose-Einstein condensates

“…In particular, the intercomponent interaction g 12 plays an important role in determining the ground state structure; when the intercomponent interaction is strongly repulsive, the two components phase separate. Adapting the Thomas-Fermi approximation, one can see that there is no solution with overlapping density profile when g 2 12 > g 1 g 2 [15,16,17,18]. This regime will be focused on in the following discussion.…”

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