Firstly, hello, I am new to the forum so please treat gently! I also not a physicist but am fascinated with quantum theory and particle physics. I have a few questions.....(sorry if they have been asked before, but having read various threads I am still confused!) Here we go. 1. If a quantum system decoheres when it loses information to the environment, then how is it that an interferrence pattern can emerge at all? Surely the wave going through the slits would decohere when hitting the back plate collapsing the wave function and creating a particle? 2. I am still confused by the outcome of a single particle in the double slit experiment. Specifically whether a single particle/wave function creates an interference pattern or not. Of what I have read it seems not. But rather many single instances build up an interference pattern. What I fail to understand is why if a single particle is infact a wave it doesn't create an interference pattern on its own? One drop into a bowl of water creates a wave, we don't have to wait for many drops? (excuse the analogy). 3. What exactly is a quantum wave a wave in? 4. If the many worlds interpretation of qt is correct why is it that we would ever see an interference pattern at all? If two universes are created for slit A and slit B, and the particle exists in universe A and B going though a different slit each, then surely we would only perceive the outcome of the universe we were in? Would we not only ever see a dot? Or are we straddling multiple universes ourselves? Which would lead to a million follow up questions....lol. 5. What distances are required for a quantum system to decohere? 6. If the wave function is merely a mathematical device the what actually creates the actual interference pattern that we see? Well that's it so far, look forward to your replies! Thanks for your help, Rcbs.