Hello, All! I'm writing a bit of fiction, and as a newcomer to the world of Quantum Physics, I thought I'd clarify a few concepts here, to avoid lapsing into technobabble. I'm trying to make something along the lines of the film Primer, which tries to incorporate as much realism as possible within the premise. For the purpose of this discussion, please understand that I'm not asking if what I'm suggesting is possible in reality. I'm ONLY asking whether, if each of the suppositions I'm making (the existence of tachyons, etc.) WERE true, what I'm suggesting would be plausible. Let's start at the beginning moving forward- To my understanding, the double slit experiment works as follows: When an electron or other particle is fired at an intervening object with two slits in it, and impacts against a backstop capable of detecting it, it's impact appears to be determined by probability. That is to say, rather than simply landing in one of 2 areas corresponding to the slots like a solid particle, it instead lands as though it were a wave- in an interference pattern determined by probability. If the experiment is modified by placing a detector over one or both of the slits, it seems to affect how it behaves. It is as if the act of measuring which slit has altered the probability of where the particle lands, reducing it so that rather than appearing to fall as an interference pattern, it lands more directly on the far side of either slot. According to theories supporting wave function collapse of superimposed states, this is because the act of observing it defines its path, causing it to fall where the observer would expect. With the variations on detector placement, some even question whether it causes retroactive changes in the behavior of the electron in question, causing it to behave as though it had been following that clearly defined trajectory all along. Regardless, they say that once it collapses, that is reality, and the other states simply cease to exist. Proponents of 'many worlds' style theories say that the wave function does not collapse to a single reality, and that it simply decoheres, and we're only capable of seeing one possible outcome. Would it be fair to say that those outcomes are still determined by probability? And now, for the sci-fi part... Suppose that tachyonic particles existed, possibly electrons somehow accelerated to superluminal speed. If we could somehow perform the double slit experiment with them, would we see them generated in an interference pattern, then travel back through the slits to the source? If we had a monitor, as with the variant on the double slit experiment, would they appear to emanate from the two areas directly beyond the slit rather than in an interference pattern? Thanks for your time! Like I said, this is fiction, so please no responses informing me that tachyons can't exist, etc. Just looking to make sure I've described the theories correctly and that my hypotheticals make some kind of sense!