I would like to ask this question. In the double slit experiment on wave particle duality of photon, we know that the wave function collapses and the photon behave like a particle whenever we peek. Has anyone ever placed a second double slit behind the detector to see whether a particle regain its wave function ? Or the particle remains a particle ? What i meant is this : Single photon ... go through double slit... peek...wave collapse... we get clump on detector ... create a hole on detector... photon go through double slit again behind the detector.. this time no peek .... on the detector, do we get interference or clump ?