if you are willing to take the maths on trust (if not, see https://arxiv.org/abs/1307.6167 and download the PDF). The key feature of quantum theory is that things are quantised – and this applies to processes, as well as to things like the amount of energy possessed by an electron in an atom. Instead of a smooth flow of time from the past to the future, there is a discrete series of events, some of which lie in the future and some of which lie in the past.
