Hi there, I've been told even with detectors behind two slits detecting if a particle comes through, that doesn't exactly mean that the quantum system is now in a mixed-state (for example, the quantum eraser experiment of Scully). How would we be able to differentiate between whether the system has collapsed or not at the screen? Even though it looks like a scatter pattern, wouldn't it really be made up of a fringe + anti-fringe interference pattern? Would we need to do some form of erasure on the detectors to determine whether the particle had gone through one slit or not? Say for example, half the time we go to detector 1 and reset it, then to detector 2 and reset it. And the other half, detector 2 and reset it, then detector 1 and reset it.