Can someone explain to me what sort of things quantum computers can/could do, based on their differences in their design, that are harder for conventional computers? So far I have a list that consists of 1) integer factorisation. I was hoping someone could extend that for me! :-) After all there are operating QC right now, so someone must be using them for something. Edit: You can get technical, if it's related to programming. QM, maybe not so :-) I have experience with software engineering that at a level that would qualify as commercial competence though I don't do it for a living.