Interfering Photons: How Paul Dirac Explained the Double Slit Experiment

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Discussion Overview

The discussion revolves around the behavior of photons in the context of the double slit experiment, particularly focusing on the concepts of wave-particle duality and the implications of measuring photon paths. Participants explore how photons can create interference patterns and the effects of measurement on these patterns.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how photons can interfere with each other if they cannot couple, referencing Dirac's statement that "the photon then interferes with itself."
  • Another participant emphasizes that photons exhibit wave-particle duality, suggesting that this duality is central to quantum mechanics.
  • A suggestion is made to refer to Feynman's lecture series for a deeper understanding of wave-particle duality and its relation to the double slit experiment and the uncertainty principle.
  • There is a query about whether firing one photon at a time results in a double slit pattern or a mixture of single and double slit patterns.
  • One participant asserts that firing one photon at a time does indeed lead to a double slit pattern, reinforcing the idea of self-interference.
  • Another participant explains that attempting to measure which slit a photon passes through destroys the interference pattern, resulting in a combination of intensities from each slit without the phase factor, linking this to the uncertainty principle.

Areas of Agreement / Disagreement

Participants generally agree that firing one photon at a time results in a double slit pattern, but there is contention regarding the implications of measurement on the interference pattern and the interpretation of wave-particle duality.

Contextual Notes

Some statements rely on assumptions about the nature of measurement and its effects on quantum systems, which remain unresolved in the discussion.

cragar
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If photon's cannot couple with other photons , then when we shoot photons through a double slit and we get an interference pattern , How are the photons interfering with the other photons , and if there is no such thing as half photon like the photon is either absorbed or it is not , then how is the localized energy of the photon interfering with the slit , Or if we shoot them one at a time will still get the inference pattern , To Quote Paul Dirac "The photon then interferes with itself " I hesitated to post this.
 
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All matter exhibits both wavelike and particle-like properties, so one can't simply imagine firing a photon like one hits a golf ball. In fact, photons are one of the prime examples of wave-particle duality.

It's actually one of the central topics of quantum mechanics, and I suggest a textbook to completely get a grasp of it.

I think this thread is what you're looking for:
https://www.physicsforums.com/showthread.php?t=57528
 
you could try reading feynman lecture series vol 3, it explains the wave particle duality in the context of double slit experiment and how it leads to the Heisenberg's uncertainity principle...it is indeed the foundation of q mech...without Heisenberg's uncertainity quantum mechanics would be meaningless!
 
okay thanks for the answers , when we fire one photon at a time is it a double slit pattern or do we get a mixture of a single slit and double slit pattern .
 
cragar said:
To Quote Paul Dirac "The photon then interferes with itself " I hesitated to post this.
You needn't have hesitated.
cragar said:
when we fire one photon at a time is it a double slit pattern[?]
Exactly, it is.
 
in a double slit set up, firing one photon at a time would lead to a double slit pattern..however if one tries to detect through which slit each photon passes one looses the double slit pattern...the resulting pattern in the latter case is mererly the addition of the intesities I1 and I2 from each of the slits. without the phase factor...this is the alternative statement to uncertainity principle...the very act of measurement disturbs the system and causes the uncertainity! reading feynamn will make it clearer !
 

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