“Observation” or “measurement” actually means interaction. We literally can’t measure anything without interacting with it. If you place something at the slits which is able to detect a photon going through, it can only do so by interacting with it.
The common way seems to be that the passing particle induces a tiny electric current in a wire loop. Obviously, that takes energy away from the particle (that energy is now in the movement of one or more electrons in the wire). And that means, its wave function in that very moment is one locational probability of 1 - it is collapsed.
“Observation” or “measurement” actually means interaction. We literally can’t measure anything without interacting with it. If you place something at the slits which is able to detect a photon going through, it can only do so by interacting with it.
The common way seems to be that the passing particle induces a tiny electric current in a wire loop. Obviously, that takes energy away from the particle (that energy is now in the movement of one or more electrons in the wire). And that means, its wave function in that very moment is one locational probability of 1 - it is collapsed.