Confinement of an ultra-cold-matter wave packet near the delocalization threshold by a waveguide bend with two or more contact impuritiesR. Méndez-Fragoso and R. Cabrera-TrujilloEur. Phys. J. D, 75 2 (2021) 40DOI: https://doi.org/10.1140/epjd/s10053-021-00047-1