Collapsing energy bands to explore their geometric structure

The geometry and topology of electronic states in solids plays a central role in a wide range of modern condensed-matter systems including graphene or topological insulators. However, experimentally accessing this information has proven to be challenging, especially when the bands are not well-isolated from one another. As reported in last week's issue of Science, an international team of researchers has devised a straightforward method to probe the band geometry using ultracold atoms in an opti