Illuminating the crystal with light reveals regions where clusters adopt opposite orientations and uncovers interactions of the collective motion of the quantum phase and atomic vibrations. Credit: Jörg M. Harms

Symmetry is one of the most fundamental principles in nature. It describes the rules that make an object look unchanged after a rotation, reflection, or other transformations. In materials, symmetry governs how atoms and electrons are arranged, and how they move together. Crucially, symmetry can even prevent certain collective atomic motions (vibrations) from interacting at all: some are simply forbidden to talk to each other. But what if those symmetry restrictions are not as rigid as they seem?

Symmetry rules loosened by electrons

A new study in Nature Physics shows that these constraints can be partially lifted.…