The mechanism by which birds and other animals detect the Earth’s very weak magnetic field has been another longstanding puzzle. Studies with the European robin demonstrate their compass is light-dependent and detects the angle of magnetic field lines relative to the Earth’s surface, rather than its orientation. Thorsten Ritz and colleagues at the University of California, Irvine, have uncovered evidence that the birds utilise an even weirder quantum process called entanglement to do this. Entanglement allows distant particle to remain instantaneously connected and is so weird that even Einstein, who remember gave us black holes and warped space-time, couldn’t believe it, disparagingly calling it ‘spooky action at a distance’. Yet, if Ritz and his colleagues are right, this spooky action is responsible for helping to guide millions of birds around the globe every year.
Interacting quantum particles may still maintain an instantaneous connection even after they have been separated by huge distance. Measurements performed on one instantaneously influences the state of the other; a feature that the sceptical Einstein dismissed as “spooky action at a distance”. Nevertheless, quantum entanglement has been demonstrated in many experimental systems and is the basis of quantum teleportation, whereby particles and codes can be instantly transported across arbitrary distances. For example, researchers recently teleported a photon 143km between the two Canary Islands of La Palma and Tenerife.