(July 13, 2020 at 10:33 am)polymath257 Wrote: Another aspect of the quantum eraser experiment is that the interference patterns only appear when the results from different detectors are compared. If you only look at one detector, there is no interference pattern seen. But, if you correlate the detectors, considering when there are linked detections, the interference pattern forms.
the interference pattern breaks down and we now have a particle distribution. this may have been interpreted as the detectors physically interfering with the photons and breaking the wave properties. but the effect is the same even when just one detector is placed over one slit. this shows that if it is known that a photon went through one slit then we have that information, but also it is known when particles that did not go through that one slit, they must have gone through the other one that does not have a detector! clever stuff. but there was still some uncertainty over what was happening. then with new technology allowing for particles to be split into entangled pairs, thereby both partners each carrying the which path information, applied to the delayed choice quantum eraser set up, it became possible to put the detectors behind the double slit thereby showing for certain that the act of observation itself is not physically interfering with the photons.
