My understanding is that the wave function will collapse if information can be retrieved, so the moment it can be known which slit it goes through, it's already

My understanding is that the wave function will collapse if information can be retrieved, so the moment it can be known which slit it goes through, it's already over. I also have a fun QM experiment idea but I could be wildly misinformed: You make two experiments, one where you fire polarized photons at a screen and one where you fire non-polarized photons. You come back some time later (irrelevant but who cares), and decide using a cosmic radiation detector (radiation still coming to us from the big bang, so truly non-deterministic) which screen to choose. You fire a regular photon and the two slits. My understanding is that if the polarized screen is chosen, the photon will come through as a particle and if not, as a wave.