Quantum physics Richard Feynman proved right after almost 80 years Karmela Padavic-Callaghan A FOUNDATIONAL postulate of quantum physics has been directly verified by an experiment for the first time. Formulated by Richard Feynman in 1948, it has long formed the backbone of much of modern physics. Quantum particles are notoriously difficult to analyse, as interacting with them affects their properties. But researchers have developed mathematical tools for predicting what a particle is likely to do under particular conditions. One such tool is the “Feynman path integral”, which posits that the most likely path a quantum particle will take between two points can be predicted by a calculation that sums all the possible paths between those points in a special way. …