Padmanabhan, T.2012-03-012012-03-012009-01-01http://hdl.handle.net/11007/31The probability amplitude for a particle to propagate from event to event in spacetime shows some nice similarities with the corresponding propagator for the electromagnetic wave amplitude discussed in the last installment. In fact this analogy provides an interesting insight into the transition from quantum field theory to quantum mechanics!enOpticsWavesQuantum mechanicsArticle