I've updated this post since this paper is now published in Foundations of Physics, at this link: https://link.springer.com/article/10.1007%2Fs10701-020-00336-6

The Afshar experiment (2005 ) is a lovely variant on the famous two-slit experiment. In this experiment, a grid is placed at the location of the dark fringes in what would be an interference pattern, but downstream from that location, the photon beam is subjected to a "which slit" measurement by way of lenses. However, … Continue reading Demystifying the Afshar Experiment →