Composite fermionization of 1-D Bose-Bose mixtures

Abstract

We study the ground states of one-dimensional Bose-Bose mixtures under harmonic confinement. As we vary the inter-species coupling strength up to the limit of infinite repulsion, we observe a generalized, composite-fermionization crossover. The initially coexisting phases demix as a whole (for weak intra-species interactions) and separate on an atomic level (for strong intra-species repulsion). By symmetry, the two components end up with strongly overlapping profiles, albeit sensitive to symmetry-breaking perturbations. Different pathways emerge in case the two components have different atom numbers, different intra-species interactions, or different masses and/or trap frequencies.