I posted this in reply to another topic in the relativity forum, but I realized this might be better as its own thread here in QP forum. I have some questions on photons being able to go faster than c. I just finished reading QED by Feynman (great book). One of the things he talks about is that when using QM pobability amplitudes to predict results you have to throw out any "common sense" notions of physics ... which, he says, includes the idea that photons move in a straight line, AND that they always travel at c. He shows this clearly for the straight line bit with the standard wall with two small holes between a source and a detector. When the the holes are small enough, then the probabilities for going straight aren't so overwhelming anymore compared to the probability for going in some weird path through another hole off to the side somewhere. However, he doesn't mention any related experiment with photon speeds, instead being careful to say for each experiment that the distances are relatively large that the photon travels, so we can assume it averages out to go c. My question is, are there experiments where the distances aren't so large where you can show that photons move faster than c? Something analogous to the 2 small holes in a wall for the path, but for the speed instead? And if so, doesn't having something moving faster than c cause all sorts of other problems? Thanks.