Fabric of the final frontier

摘要

Particles flying through space and blindly follow the path set by any forces that are acting on them. Apart from these forces, four dimensional space-time itself is nothing but a blank canvas, a featureless backdrop against which everything plays out. So no matter what direction or speed a particle is moving at, its behaviour is the same. This picture underlies the whole of modern physics in the form of a principle called Lorentz symmetry. But not everyone is happy with it. Instead of being a directionless backdrop, space could just as easily be dotted with minuscule invisible arrows that exert a subtle influence on particle behaviour. Imagine space-time wearing a pinstripe suit, with the pinstripes formed by rows of these tiny arrows. Any particles flying past will be weakly influenced by the pinstripes. The spin of electrons, the polarisation of photons, or the energy levels of atoms will be changed ever so slightly, depending on their direction and speed as they travel through the pinstriped space.