Phonon vs Photon: What's the Difference?

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Discussion Overview

The discussion centers on the differences between photons and phonons, exploring their definitions, interpretations, and the contexts in which they are understood. The scope includes theoretical perspectives from quantum electrodynamics (QED) and condensed matter physics, as well as implications for mainstream and non-mainstream physics.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants define photons as quanta of the electromagnetic field and phonons as collective excitations of lattices in condensed matter.
  • Others propose that photons can also be interpreted as quasi-particles resulting from collective excitations, particularly in action-at-a-distance theory electrodynamics.
  • A distinction is made between photons as elementary particles in quantum electrodynamics (QED) and phonons as always consisting of underlying structures.
  • Some participants question the relevance of certain interpretations and request clarification on terms like "coherent state" and "AAAD QED" (Action-At-A-Distance QED).
  • There are references to the American Physical Society and Reviews of Modern Physics, with some participants arguing about the mainstream status of certain theories and resources.
  • Concerns are raised about the relevance of non-mainstream theories to the original question, with some participants suggesting that these discussions may confuse the original poster.
  • Some participants express skepticism about the mainstream acceptance of certain interpretations and highlight the need for independent resources to support claims.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and interpretations of photons and phonons, with no consensus reached on the relevance of certain theories or the mainstream status of the discussed concepts.

Contextual Notes

Limitations include the potential for misunderstanding of terms like "coherent state" and "AAAD QED," as well as the unresolved status of certain theories in relation to mainstream physics.

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What is the difference between the photon and the phonon ?
 
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Photons are quanta (particles) of the electromanetic field; phonons are collective excitations (quasi particles) of lattices in condensed matter.
 
Thank you.
 
tom.stoer said:
Photons are quanta (particles) of the electromanetic field; phonons are collective excitations (quasi particles) of lattices in condensed matter.

Photons can be also interpreted as quasi particles resulting from collective excitations. This is specially true in action-at-a-distance theory electrodynamics, where electromagnetic fields do not exist as material systems.
 
juanrga said:
Photons can be also interpreted as quasi particles resulting from collective excitations. This is specially true in action-at-a-distance theory electrodynamics, where electromagnetic fields do not exist as material systems.
What do you have in mind? In QED photons are elementary particles, whereas phonons always consist of underlying structures.
 
juanrga said:
Photons can be also interpreted as quasi particles resulting from collective excitations. This is specially true in action-at-a-distance theory electrodynamics, where electromagnetic fields do not exist as material systems.

Do you mean something like a coherent state?
 
tom.stoer said:
What do you have in mind? In QED photons are elementary particles, whereas phonons always consist of underlying structures.

In field-theoretic QED photons are the particles associated to the EM field. IN AAAD QED, there is not EM field and photons are quasiparticles
 
jfy4 said:
Do you mean something like a coherent state?

I do not know what do you mean by coherent state, but I think is unrelated.
 
juanrga said:
In field-theoretic QED photons are the particles associated to the EM field. IN AAAD QED, there is not EM field and photons are quasiparticles
What is AAAD QED? Can you provide some explanations or references? How is this related to the original question which can be interpreted as a question regarding mainstream physics?
 
  • #10
tom.stoer said:
What is AAAD QED? Can you provide some explanations or references? How is this related to the original question which can be interpreted as a question regarding mainstream physics?

AAAD = Action-At-A-Distance

http://rmp.aps.org/abstract/RMP/v67/i1/p113_1

Because your answer is only a half of the modern picture...
 
  • #11
juanrga said:
AAAD = Action-At-A-Distance

http://rmp.aps.org/abstract/RMP/v67/i1/p113_1

Because your answer is only a half of the modern picture...
Sorry, my answer is approximately 99.999% of the modern picture; but what you propose is not 'the modern picture' at but definitely beyond standard (mainstream) physics. That does not mean that it's wrong, but it's definitely irrelevant for this thread and confusing for the OP.
 
  • #12
tom.stoer said:
Sorry, my answer is approximately 99.999% of the modern picture;

Agree with a systematic error of about a 75% in your number :rolleyes:.

tom.stoer said:
but what you propose is not 'the modern picture' at but definitely beyond standard (mainstream) physics.

Agree again with you, the American Physical Society, and Reviews of Modern Physics are well-known non-mainstream resources :wink:.

tom.stoer said:
That does not mean that it's wrong, but it's definitely irrelevant for this thread and confusing for the OP.

Yes, it is best to repeat semi-correct clichés, without being aware of modern avenues of research.
 
  • #14
juanrga said:
Agree again with you, the American Physical Society, and Reviews of Modern Physics are well-known non-mainstream resources :wink:.

RMP is especially devoted to "recent work of interest to all physicists, especially work at the frontiers of physics" as the APS states. As such it is indeed also aiming at non-mainstream positions. For a RMP, 18 indexed citations in 16 years also mean more or less that the topic is certainly not mainstream.

The stuff by Hoyle and Narlikar follows Wheeler's and Feynman's absorber theory and aims at steady-state cosmology which is in any way far from mainstream. It is somewhat correct physics (although difficulties with the microwave background given by WMAP results arise which might, however, be settled), but definitely not mainstream.
 

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