The universe as a string-net liquid,

Different phases of matter are characterised by the way their atoms are organised. In a liquid, for instance, atoms are randomly distributed, whereas atoms in a solid are rigidly positioned in a lattice. FQHE systems are different. "If you take a snapshot of the position of electrons in an FQHE system they appear random and you think you have a liquid," says Wen. But step back, and you see that, unlike in a liquid, the electrons dance around each other in well-defined steps.

It is as if the electrons are entangled. Today, physicists use the term to describe a property in quantum mechanics in which particles can be linked despite being separated by great distances. Wen speculated that FQHE systems represented a state of matter in which entanglement was an intrinsic property, with particles tied to each other in a complicated manner across the entire material.

This led Wen and Levin to the idea that there may be a different way of thinking about matter. What if electrons were not really elementary, but were formed at the ends of long "strings" of other, fundamental particles? They formulated a model in which such strings are free to move "like noodles in a soup" and weave together into huge "string-nets".


They've found what might be an example of this state of matter on Earth, a mineral called herbertsmithite.