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I think this video is a good explanation you can use to refer to people with that misunderstanding: https://www.youtube.com/watch?v=sQfSm6o-KlQ https://www.you

• Strilanc 11y ago
  The main problem with that series of videos, if I remember correctly, is that it only ever gives high-level descriptions of experiment outcomes. Those are interesting, but they aren't really good explanations. Then to top that off, they get some of the important details wrong. For example, in the quantum eraser video referred to by the video you linked, it's said that there's an interference pattern for B when you don't measure the entangled associated photon A (and that there is one when you do measure A). That's not the case. If it was the case, we'd have a handy-dandy FTL communication mechanism. What actually happens is that there's never a visible interference pattern for B in this experiment. Instead, you use the measurements of A to filter or split the measurements of B into two groups (e.g. Bs when A up, Bs when A down). Within each group of measurements, you'll find an interference pattern. The two interference patterns will complement each other so the sum is an apparent lack-of-interference; you need the As to do the separation. I personally think the the quantum eraser experiment has a terrible misleading name. It's more of a "use entangled measurements to find the interference" experiment.