Simplified Afshar experiment: many-worlds interpretation

[johne1618]

Hi,

I would be interested in what people think of the following experiment.

Imagine a laser beam is split into two coherent beams A and B that are made to cross each other at right-angles. Beyond the point of intersection let us assume that there is a detector A in the path of beam A and detector B in the path of beam B.

In the region where the beams intersect there will be parallel diagonal planes of constructive and destructive interference separated by a wavelength.

Now let us block both of the beams A and B before they reach the intersection point.

Next we place a thin absorbing layer, whose thickness is much less than a wavelength, at the position of one of the diagonal planes of destructive interference.

Now we open each of the beams A or B alone and verify that the beam is absorbed by the thin absorbing layer so that neither detector A or B fires.

Now we open both of the beams A and B together.

The two beams now reach both sides of the diagonal absorber in such a way that there is destructive interference of their amplitudes in the plane of the absorber. Thus the probability of the absorber absorbing a photon is zero.

I believe now that the beams will "leap-frog" the absorber so that half the time detector A detects a photon and half the time detector B detects a photon.

How could we interpret such a result?

Let us assume detector A fires. By conservation of momentum we can track back along the path A that the photon must have taken up to the diagonal absorber.

But how did it get through the absorber?

I submit that the only way it got through was that, using David Deutsch's phrase, a "shadow" photon passed along path B at exactly the same time such that it destructively interfered with the path A photon allowing them both to avoid being absorbed.

That shadow photon must have been detected by detector B in a "parallel" world.

That parallel version of the experimenter makes the same argument, tracking back his shadow photon along path B, and thus reasons that another photon traveling along path A must have crossed the absorber at exactly the same time as his photon and must have been detected by detector A in a parallel world.

John

 

[AndyW]

I find this experiment to be very interesting and thought-provoking. The idea of parallel worlds and shadow photons is a fascinating concept that has been explored in various theories and interpretations of quantum mechanics. However, before drawing any conclusions from this experiment, it is important to consider potential flaws and limitations.

Firstly, the experiment assumes that the absorber is thin enough to allow for the "leap-frogging" of the photons. This may not always be the case in practical experiments, and the thickness of the absorber could potentially affect the results. Additionally, the experiment relies on the assumption that the two beams are perfectly coherent and that the detectors are able to accurately measure the absorption of the photons. Any slight deviations or imperfections could affect the results.

Furthermore, this experiment does not take into account other factors that could influence the behavior of the photons, such as external forces or interactions with particles in the environment. It is possible that these factors could also play a role in the observed results.

In terms of interpretation, there are various theories and explanations that could be used to explain the results of this experiment. The idea of parallel worlds and shadow photons is just one possibility, and there may be other interpretations that could also fit the data.

Overall, this experiment raises interesting questions and offers potential insights into the behavior of photons. However, further research and experimentation would be needed to fully understand and interpret the results.