Beyond Thomas--Fermi analysis of the density profiles of a miscible two-component Bose--Einstein condensate

Abstract: We investigate a harmonically trapped two-component Bose--Einstein condensate within the miscible regime, close to its boundaries, for different ratios of effective intra- and inter-species interactions. We derive analytically a universal equation for the density around the different boundaries in one, two and three dimensions, for both the coexisting and spatially separated regimes. We also present a general procedure to solve the Thomas--Fermi approximation in all three spatial dimensionalities, reducing the complexity of the Thomas--Fermi problem for the spatially separated case in one and three dimensions to a single numerical inversion. Finally, we analytically determine the frontier between the two different regimes of the system.