Physicists have peered through the proverbial looking glass, and the atoms on the other side belong to a world of opposites. For the first time, researchers have made an exotic quantum object called an Alice ring, which changes the properties of other quantum objects when they pass through it – or when they are simply viewed through it.

Quantum systems – such as collections of very cold atoms, or even our whole universe – should theoretically contain strange objects called topological defects. Some