When parallel worlds collide, quantum mechanics is born

Parallel universes – worlds where the dinosaur-killing asteroid never hit, or where Australia was colonised by the Portuguese – are a staple of science fiction. But are they real?

In a radical paper published this week in Physical Review X, we (Dr Michael Hall and I from Griffith University and Dr Dirk-André Deckert from the University of California) propose not only that parallel universes are real, but that they are not quite parallel – they can "collide".

In our theory, the interaction between nearby worlds is the source of all of the bizarre features of quantum mechanics that are revealed by experiment.