A sheet of graphene is a mesh of carbon atoms one atom thick. Even the slightest contamination shows up on it, like dust specks on eyeglass lenses. Ten years ago, researchers learned to hide graphene between layers of boron nitride, like placing a fragile sheet between two pieces of plastic wrap. But even in such packaging, charged impurities remained, hindering the free movement of electrons.

It turns out that a short flash of deep ultraviolet light neutralizes these impurities. The light knocks out excess charges, and the graphene becomes on average a hundred times cleaner. After such treatment, rare fractional quantum states appeared in ordinary devices — electrons there behave as if they split into parts. Some of these states may be non-Abelian: their order changes in a special way when particles are exchanged, which is important for future quantum computers.

The method is simple and fast: just hold the finished device under a deep ultraviolet lamp. It's like wiping your glasses with a special cloth: you immediately see more details. Now researchers have an easy way to obtain graphene of exceptional quality to study exotic quantum phenomena without interference.