The structure of quantum theory suggests a wide range of metaphors to describe the nature of time. A patchwork quilt, a piece of cloth consisting of tightly intertwined threads, a garden of forking paths, a probability tree or Russian matrushka dolls all constitute worthy candidates.
Of course, in a linear text, the best such metaphor, which incidentally happens to be a superset of all the other metaphors, could be kept hidden from the reader until the end.
The main premise behind a quantum view of time is simple. At any point in time, the future remains a tabula rasa, a clean slate, a blank sheet of paper, an empty glass, a bald head, an unfinished symphony. The actions of all entities within an instant of time defines the next instance, and that instant in turn does the same for the next instance, and so on ad infinitum. The notion of the infinitesimal, first defined by Isaac Newton as the smallest unit of existence, can be applied to the concept of time to give rise to even further philosophical questions: What is an instant? How far can you go dividing an instant in half until you can proceed no more? Can you define the atomic unit for time, as science has tried, and failed miserably, with space? However, more questions will probably be of little use before we can answer the main one.
Defining time as such a recursive function operating on the past and the present seems to explain things somewhat, although the theory is by no means entirely satisfactory. How are 'potential futures' framed? Is there a discrete range of possible futures with slight variations, or can you really, as the vision of the American dream once led millions to believe, create your future the way you want it to be?
These questions define the point where the fiction takes over the science in science fiction. Some experts suggest the existence of 'attractor' quantum branches, much like the attractor regions in fractal geometry, and any quantum branch reasonably close to the attractor will gradually move closer to, and ultimately fuse with, this main branch. For instance, if I will become a professional murderer in five years, the fact that I had cereal rather than pancakes for breakfast this morning will not change things much. The passing time therefore has a dampening effect on events so that nearby branches ultimately converge with this most probable timeline, popularly known as fate.
This theory allows for the possibility of a finite number of attractor quantum branches, as well as the possibility that there exists a unique timeline which all quantum branches will ultimately fuse with, the best of all possible universes. Of course, the theory that any moment in time is a quantum seed which can give rise to an infinitude of quantum seeds, which can each in turn do the same, and thereby create an infinitude of timelines in all possible directions, is equally credible.
We cannot differentiate between the science and the fiction among these theories until we hear about the time machine on the evening news.