EPR experiment with twin photons then interference experiment

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Discussion Overview

The discussion revolves around the implications of the EPR paradox in the context of twin photons and their behavior in interference experiments. Participants explore whether an unobserved photon, whose polarization is inferred from its entangled twin, can produce an interference pattern when subjected to an interference experiment.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant proposes that after observing the polarization of one twin photon, the polarization of the unobserved twin can be inferred, raising the question of whether this unobserved photon can produce an interference pattern in an experiment.
  • Another participant requests clarification on what is meant by an "interference experiment," specifically asking what the unobserved photon would be interfering with.
  • A later reply reiterates the question about self-interference of the unobserved photon, emphasizing the need for clarity on the experimental setup.
  • One participant asserts that in general, entangled photons do not produce interference patterns due to insufficient coherence, referencing a specific source for this claim.
  • Another participant acknowledges the response and expresses appreciation for the provided information and reference.

Areas of Agreement / Disagreement

There is no consensus on whether the unobserved photon will produce an interference pattern, as one participant asserts it will not due to coherence issues, while others have not provided a counterargument or alternative perspective.

Contextual Notes

The discussion does not resolve the assumptions regarding coherence and the specific conditions under which interference might or might not occur with entangled photons.

TeCNoYoTTa
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If we have twin photons moving in the opposite direction.

For the first photon we can pass it through a polarizer that will either output a photon with vertical polarization or a photon with horizontal polarization.

after this experiment we now know what will the other unobserved photon polarization will be if it passes through this polarizer (EPR paradox)

My question is .. what will be the results if we used the unobserved photon in an interference experiment. will it produce an interference pattern ?
 
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You'll have to tell us a lot more about what you mean by an "interference experiment", starting with what the particle will be interfering with.
 
Nugatory said:
You'll have to tell us a lot more about what you mean by an "interference experiment", starting with what the particle will be interfering with.

I am asking if it will interfere with it self. this single unobserved photon that we knew it's polarization by observing the polarization of it's twin. but the photon it self is unobserved.

If we did this experiment multiple times. will there be an interference pattern ?
 
TeCNoYoTTa said:
I am asking if it will interfere with it self. this single unobserved photon that we knew it's polarization by observing the polarization of it's twin. but the photon it self is unobserved.

If we did this experiment multiple times. will there be an interference pattern ?

As it happens, the answer is NO. In the general case, entangled photons do not produce interference because they are not sufficiently coherent.

See Zeilinger, page 290, figure 2, there is no direct interference pattern for entangled photons:

Experiment and the foundations of quantum physics (1999)[/QUOTE]
 
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DrChinese said:
As it happens, the answer is NO. In the general case, entangled photons do not produce interference because they are not sufficiently coherent.

See Zeilinger, page 290, figure 2, there is no direct interference pattern for entangled photons:

Experiment and the foundations of quantum physics (1999)
[/QUOTE]

Thanks for the answer and the interesting link
 

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