Lauriane Chomaz

Two dancers on one stage: the triangle and the stripe. In a quantum gas of dysprosium atoms cooled to 62 nanokelvin, these two spatial structures have met for the first time in a single experiment. The gas is held in a trap shaped like a surfboard, and its atoms are among the most magnetic in the periodic table.

In an ultracold cloud of 180,000 lithium atoms, about a thousand cesium atoms drift. They are 22 times heavier than their neighbors, which makes them nearly motionless among the fast-moving particles. When such a heavy atom absorbs light, it starts oscillating between two states, and the rate of these oscillations is called the Rabi frequency.