The grey smudges on this much-magnified nuclear emulsion detector may not look much, but they are highly significant.
This is the physical evidence generated by researchers from the University of Bern in Switzerland which proves that positrons – the anti-particle to the electron – behave according to the wave-particle duality predicted by quantum theory.
Wave-particle duality has already been conclusively shown in experiments using electrons and neutrons, as well as some quite large molecules. Demonstrating it using just a single positron, however, had never been attempted.
“Our observation of the energy dependence of interference pattern proves its quantum-mechanical origin and thus the wave nature of the positrons,” says Paola Scampoli, co-author of a paper published in the journal Science Advances.