Why doesn't decoherence spoil the double slit experiment? Imagine firing one electron at a time at a double slit. Clearly the wave function interacts with the atoms of the material, and presumably many electrons do not pass through. Why does decoherence from these interactions not spoil the experiment?
The question has been asked before, but there is no answer
Edit, to clarify the question: since the electron wave function interacts with the atoms of the material in which the double slit is cut, I naively expect that decoherence would make the system classical,  no matter how carefully the experiment is set up. I must be misunderstanding the decoherence mechanism that prevents macroscopic systems being in quantum superpositions. The question is, why doesn't this decoherence spoil the double slit experiment? Can anyone explain why decoherence ensures Schrodinger's cat is alive or dead, but does not ensure the electron goes through one slit or the other?
 A: One should distinguish the idealized model discussed in textbooks and real interferometers. Decoherence is indeed an issue in many experiments, which is why realizing such interferometers in practice has been challenging.
What is more surprizing, is that some degree of decoherence is present even in the simplest discussions of the two-slit experiment, as not all the particles arrive at the screen - some of them escape in space, while others land on the non-transparent part of the wall with the slits. Thus, the first attempts of literally realizing an Aharonov-Bohm experiment in solid state devices, with the two particle beams confined within two waveguides (arms of a ring) resulted in phase rigidity - AB oscillations with phase either $0$ or $\pi$. To make the phase change continuously, one had to introduce artificially particle losses, as in this paper. Since then the decoherence in AB interferometers was studied extensively, both experimentally and theoretically. There have been even proposals of using controlled decoherence for measurements, as here.
