L. Martinelli

In the crystal La₂₋ₓSrₓCuO₄, at a certain composition, two states coexist: superconductivity, where electrons move without loss, and a charge-density wave — a periodic bunching of electron density. These states compete for the same electron clouds, which resemble cross-shaped petals.

In a lab where crystals are studied, a technician stares at a screen covered in bright spots and slowly rotates the sample, trying to get the spots to form a symmetric pattern. It's like tuning an old radio: you turn the knob until the static gives way to a clear signal. Now, a machine can turn that knob. Scientists have created a program that learns to align crystals without any knowledge of how those spots work.