All three phenomena are commonly observed in classical liquids, but the study authors demonstrated their occurrence in an ultracold mixture of potassium and rubidium atoms. This is probably the first time an atomic gas has shown such behavior.
Exploring capillary instability in a quantum gas
The study authors observed that when an ultradilute quantum gas (the potassium rubidium atomic mixture) was brought down to temperatures approaching absolute zero, it remained in the gaseous phase but at the same time exhibited liquid-like properties and formed a single quantum droplet.
This droplet was then placed in a laser-created path, where it stretched into a thin line. The elongated quantum droplet, when stretched beyond a critical length, became unstable and broke into smaller droplets.