Observation of quantum droplets in a heteronuclear bosonic mixture

This work reports on the observation of quantum droplets in a two-species bosonic mixture with attractive interspecies interaction. Their dynamics is studied both in free space and in an optical waveguide, providing a clear picture of the droplet formation and evolution. Remarkably, the mixture employed in this experiment --- formed by 41K and 87Rb atoms --- makes possible the realization of long-lived droplets, thus opening new avenues for research on such dilute, self-bound quantum states.