Dispersion Relation: What is it for Photons?

Click For Summary

Discussion Overview

The discussion centers on the concept of dispersion relations specifically for photons, exploring the relationship between frequency and wave number, as well as the implications for phase speed and index of refraction in various media.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • Some participants define a dispersion relation as the relationship between frequency (omega) and wave number (k).
  • Others discuss how the phase speed of light and the index of refraction depend on the light's frequency in specific materials or media.
  • One participant questions the restriction of the discussion to light, suggesting that dispersion relations apply to all types of waves.
  • A later reply acknowledges the initial question about photons while reiterating the broader context of dispersion relations.
  • Another participant presents the dispersion relation for photons as ω = |k|c.
  • One participant expresses understanding of the discussion, indicating engagement with the topic.

Areas of Agreement / Disagreement

Participants express varying degrees of agreement on the definition and implications of dispersion relations, with some focusing specifically on photons while others advocate for a broader interpretation that includes all waves. The discussion does not reach a consensus on the scope of dispersion relations.

Contextual Notes

Some assumptions about the definitions of terms like frequency and wave number may not be explicitly stated, and the discussion does not resolve the implications of dispersion relations across different types of waves.

yellowgold
Messages
12
Reaction score
0
What is the dispersion relation in photons? "(Frequency momentum or etc)
 
Physics news on Phys.org
A dispersion relation is the relation between the frequency omega and the wave number k.
 
Or, said in another way, how the phase speed of light (and hence, the index of refraction) depends on the light's frequency in that specific material/medium.
 
lightarrow, why restrict yourself to light? The dispersion relation are for waves, all waves, as far as I have understood it.
 
malawi_glenn said:
lightarrow, why restrict yourself to light? The dispersion relation are for waves, all waves, as far as I have understood it.
Ah, yes, of course, but the OP asked about photons.
 
lightarrow said:
Ah, yes, of course, but the OP asked about photons.

haha yeah now I saw he did! ;-)
Though he asked what dispersion relation was "in general"
 
The dispersion relation for photons is
\omega=|\vec k|c.
 
Thank you very much everybody. I understood it.
 

Similar threads

Undergrad What is the significance of the dispersion relation?
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Dispersion Relation in Different Media
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Dispersion relation and their origins & meaning
  • · Replies 3 ·
Replies
3
Views
3K
Graduate Dispersion relation for non-relativistic quantum particles
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Dispersive approximation (limit) in the Jaynes-Cummings Model
  • · Replies 1 ·
Replies
1
Views
1K
Undergrad Is there a multicolor single photon?
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Is photon energy negative in a negative-index metamaterial?
  • · Replies 11 ·
Replies
11
Views
2K
Heat capacity from dispersion relation
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Understand Electronic Dispersion: Definition & Examples
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Do EM waves have negative frequency inside negative-index materials?
  • · Replies 4 ·
Replies
4
Views
2K