Double slit experiment with magnets

1. May 19, 2014

Commando Spaz

Hi everyone,

Lately I have been reading about the double slit experiment, I am wondering if it would be possible to recreate this experiment with visibly large objects using magnetism. The experiment I was thinking might be able to do this is as follows:

There are two vertical tubes, a magnet has a fifty percent chance of falling through the left tube, and a fifty percent chance of falling through the right tube. Beneath each tube is a ledge and a fan of a very erratically changing speed. The magnet will land on one of the ledges (depending on which tube it came down from), be blown off, and come to rest on a floor below and between the ledges. The fan would blow the magnet in such a way that the probability of it landing at any one point on the floor would decrease with the distance from the ledge it was blown off, so it would be more likely for the magnet to fall on the edges of the floor than in the centre. However, the erratic nature of the speed of the fan would ensure that the magnet could be blown from either ledge to land on any part of the floor between them. Thus it would be impossible to tell with 100% confidence which tube the magnet originally fell from based only on its final resting position on the floor, although it would be possible to calculate the probability that it came down either tube.
The ledges are close enough to each other, and the floor is far enough below the ledges that if one magnet was blown off each ledge simultaneously they would always be brought together by magnetic attraction before landing on the floor below. This would mean that they would be more likely to land in the center of the floor than the edges. Thus a series of pairs of magnets falling through each tube simultaneously would yield an inverted pattern as opposed to magnets falling randomly through either tube one at a time.

My question is: what would happen if the magnets fell randomly through either of the tubes one at a time, but the process was not observed? i.e. only the only information collected was where they landed. Would the pattern be like that produced when the magnets fell through simultaneously (i.e. concentrated in the centre of the floor)? or would it be the same as if the process (i.e. which tube each magnet had fallen through) had been observed? I tried to attach a ppt presentation to help visualize the experiment but it wouldn't attach, sorry. Please explain your answers, I'm not trying to make a statement, I just want to know what would happen.

Thanks

2. May 19, 2014

Staff: Mentor

No. You'll never get coherence between your paths.

It would be. Your magnet is interacting with the gas in the tubes, with light (even thermal radiation), and basically with everything else. As an accelerated magnet, it would emit electromagnetic radiation, and so on. There is no way to switch that off with the setup you have in mind. It is hard enough to do this with larger molecules.
Your experiment would be purely classical.

3. May 19, 2014

Commando Spaz

Thanks mfb,

Would the result be the same if this experiment were conducted in a vacuum, and far enough underground to sufficiently reduce background radiation?

4. May 20, 2014

Staff: Mentor

Yes. Even in a hypothetical perfect vacuum.
This has nothing to do with cosmic radiation.