Quantum Pileup: Ultracold molecules meld into oneness

Two independent teams of physicists have coaxed molecules into an extraordinary state of ultracold matter previously demonstrated only with atoms.

ALL FOR ONE. Released from a trap, an ultracold cloud of potassium molecules (right) barely disperses–a sign that nearly motionless molecules have condensed into a new form of matter. Slightly warmer cloud (left), which hasn’t condensed, spreads after release.