2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/187929A presentation and a generalisation are given of the phenomenon of level rearrangement, which occurs when an attractive long-range potential is supplemented by a short-range attractive potential of increasing strength. This problem has been discovered in condensate-matter physics and has also been studied in the physics of exotic atoms. A similar phenomenon occurs in a situation inspired by quantum dots, where a short-range interaction is added to an harmonic confinement.12 pages, 11 figures, RevTeX4Mesoscale and Nanoscale PhysicsNuclear TheoryQuantum Physicstext