2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/107895Based on an experimental study of two-body and three-body collisions in ultracold strontium samples, a novel optical-sympathetic cooling method in isotopic mixtures is demonstrated. Without evaporative cooling, a phase-space density of $6\times10^{-2}$ is obtained with a high spatial density that should allow to overcome the difficulties encountered so far to reach quantum degeneracy for Sr atoms.5 pages, 4 figuresAtomic Physicstext