First “Quantum Rain” Observed in Florence

A research team from the CNR, the University of Florence and Lens has observed for the first time the formation of rows of quantum droplets in ultracold mixtures of atoms. The study, published in Physical Review Letters, demonstrates how surface tension, a phenomenon typical of classical liquids, causes an atomic filament to break into drops even in an ultra-dilute quantum gas.

The experiment, conducted in the Quantum Mixtures laboratory of the CNR-INO and led by Alessia Burchianti, revealed that a quantum droplet of potassium and rubidium, released in a laser waveguide, elongates until it breaks into multiple drops, replicating the Plateau-Rayleigh capillary instability observed in classical liquids. This result represents an important advance in the understanding of quantum liquids and opens new perspectives for applications in quantum technologies.

The study was supported by initiatives funded under the PNRR, including the I-PHOQS infrastructure, which provides essential tools for research in photonics and quantum sciences.