Query on use of prism in delayed choice quantum eraser experiment

In summary, the Delayed Choice Quantum Eraser experiment involves various schematic diagrams, some of which include a prism to diverge the two idler photon paths. However, the way in which the prism is shown refracting the 'idler rays' in these diagrams contradicts Snell's law. It is unclear if this is a mistake or if there is a misunderstanding. One of the diagrams also has incorrect ray paths through the Glan-Thomson prism. A correct diagram has been found, but concerns about copyright have been raised.
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Steve4Physics
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Query on use of prism in delayed choice quantum eraser experiment
Hi. I’ve seen a number of schematic diagrams for the Delayed Choice Quantum Eraser experiment. Some include a prism to make the two idler photon paths diverge.

However, the prism is shown refracting the ‘idler rays’ in a way which contravenes Snell’s law. E.g. see prism marked ‘PS’ (not the Glan-Thompson prism) here:
Eraser.png


(from https://en.wikipedia.org/wiki/Delayed-choice_quantum_eraser)

Is this a mistake or have I misunderstood something? Thanks.
 
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Steve4Physics said:
However, the prism is shown refracting the ‘idler rays’ in a way which contravenes Snell’s law. E.g. see prism marked ‘PS’ (not the Glan-Thompson prism) here:
Hmmm. I doubt the prism in the diagram is supposed to show the actual path of light in the experiment.
 
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Drakkith said:
Hmmm. I doubt the prism in the diagram is supposed to show the actual path of light in the experiment.
Yes. It seems that part of the diagram is a bit of a 'bodge'. But the rest of the diagram seems OK. But I've found similar diagrams showing the same thing, so it's very puzzling.
 
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No one is worried about Snell's law when they're throwing shapes and lines into powerpoint. :wink:
 
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Drakkith said:
No one is worried about Snell's law when they're throwing shapes and lines into powerpoint. :wink:
I guess so. But it's much more than a minor misjudgement of angles.

And I noticed another mistake in the diagram. The ray paths through the Glan-Thomson prism (just after the SPDC non-linear crystal) are wrong.

Maybe I'm just being too picky!

With a bit of searching (using Google Images) I've now found a diagram which appears correct. I’m not sure about copyright so here's just the link:
https://www.researchgate.net/public...-delayed-choice-quantum-eraser-experiment.ppm
 
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FAQ: Query on use of prism in delayed choice quantum eraser experiment

What is a delayed choice quantum eraser experiment?

A delayed choice quantum eraser experiment is a thought experiment in quantum mechanics that demonstrates the concept of wave-particle duality. It involves sending a particle through a double-slit apparatus, which creates an interference pattern. However, the experiment also includes a "quantum eraser" device, which can erase the information about which path the particle took, causing the interference pattern to disappear.

How does a prism play a role in this experiment?

In a delayed choice quantum eraser experiment, a prism is used to split the incoming light into two beams, which are then sent through the double-slit apparatus. The prism is necessary to create the interference pattern, as it allows for the two beams to overlap and interfere with each other.

What is the purpose of using a prism in this experiment?

The purpose of using a prism in a delayed choice quantum eraser experiment is to demonstrate the concept of wave-particle duality in a more tangible way. By splitting the light into two beams, the experiment shows how the same particle can behave like a wave and exhibit interference patterns, or like a particle with a definite path, depending on whether or not the information about its path is observed.

Can a different device be used instead of a prism in this experiment?

Yes, a different device, such as a diffraction grating, can be used instead of a prism in a delayed choice quantum eraser experiment. The important factor is that the device is able to split the incoming light into two beams, which can then be sent through the double-slit apparatus to create the interference pattern.

What is the significance of the delayed choice quantum eraser experiment?

The delayed choice quantum eraser experiment is significant because it challenges our understanding of the nature of reality and the role of observation in quantum mechanics. It suggests that the behavior of particles is not determined until they are observed, and that the observer has the power to influence the outcome of an experiment. This has implications for our understanding of the fundamental laws of the universe and the nature of consciousness.

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