Zheng Li

The crystal of RbMn6Bi5 resembles a five-story building of manganese atoms, where the residents on each floor form a pentagon. At room temperature, the magnetic moments of the atoms fluctuate chaotically, like compass needles during a magnetic storm.

A tuning fork sounds incredibly pure, but touch it and the pitch changes almost instantly. Engineers faced a similar challenge: creating a laser that simultaneously possesses two seemingly incompatible properties — exceptional spectral purity (a very narrow emission line, like a tuning fork producing a single note without wobble) and the ability to rapidly tune that frequency.