Misc. Trouble with DIY Quantum Eraser Experiment?

[jimjones]

Hello,

I am trying to perform the DIY quantum eraser experiment, but I'm having some trouble. When I perform the classic double slit experiment using a cheap laser pointer and a piece of wire I get a beautiful interference pattern as expected. However when I try the DIY QE experiment I still get an interference pattern, but slightly smudged. I'm using cheap cardboard 3D glasses for the polarizers. I lined up perpendicular pieces and cut them straight. I butted them up against each other and covered the joint with a piece of wire. I've double checked the alignment of the polarizers several times, but I'm still getting the interference pattern. Could my laser pointer be too low quality? Are the polarizing lenses ineffective? Or do I misunderstand the experiment? Any help would be appreciated.

Thanks.

 

[Joseph14]

I'm unfamiliar with the DIY QE experiment. Can you provide a link.

 

[Joseph14]

ok I found it.

two questions

1) did you test the polarizers (by putting them on top of each other) to ensure that all light is being blocked by their combination?
2) did you make sure you then took them and placed them side by side without changing their orientation (including flipping front and back)? The front and back side of some polarizers are different.

 

[Joseph14]

here it is for other people
http://www.scientificamerican.com/slideshow.cfm?id=a-do-it-yourself-quantum-eraser

I don't think this actually is a real quantum eraser experiment at all. The results do not rely on knowledge of paths destroying the self interference. Knowledge of the paths wouldn't remove interference in this case because there are multiple photons so we don't just need to worry about self interference. This experiment claims that the polarization marks the streams, however it doesn't just mark the particles it also polarizes them. The polarization alone completely explains the results.

 

[jimjones]

Yes, I've double checked the orientation of the polarizers many times, they are perpendicular.

ok I found it.

two questions

1) did you test the polarizers (by putting them on top of each other) to ensure that all light is being blocked by their combination?
2) did you make sure you then took them and placed them side by side without changing their orientation (including flipping front and back)? The front and back side of some polarizers are different.