First theorized in 1973 by physicist Philip W. Anderson, quantum spin liquids are exotic phases of matter with topological order. They feature long-range quantum entanglement that can potentially be exploited to realize robust quantum computation. But the problem about this exotic state of matter has been its very existence: no one had ever seen it — at least, that had been the case for almost five decades.

“Instead, it’s all about magnets that never freeze and the way electrons in them spin.”