What is a photon in terms of EM waves?

  • Thread starter k9b4
  • Start date
  • #1
109
2

Main Question or Discussion Point

Is it one wavelength of EM wave? I have googled for this and I can't find an explanation for what a photon is in terms of EM waves.
 

Answers and Replies

  • #2
Orodruin
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
Gold Member
16,817
6,624
This is a complicated issue. The photon is the smallest possible excitation of the quantized electromagnetic field. It really does not make much sense to think of it as a classical EM wave, because it is not. Classical EM fields are better described by coherent quantum states.
 
  • #3
29,561
5,884
Is it one wavelength of EM wave? I have googled for this and I can't find an explanation for what a photon is in terms of EM waves.
It is most definitely not one wavelength of an EM wave.

Quantum electrodynamics (the theory of photons) is a more general theory than classical electrodynamics (the theory of EM waves). Thus, you can explain what classical EM waves are in terms of photons, but not the other way around.

There simply is no classical EM analog of a photon, but there is a quantum analog of a classical EM wave, the coherent state that Orodruin mentioned.
 

Related Threads on What is a photon in terms of EM waves?

Replies
13
Views
1K
  • Last Post
Replies
8
Views
2K
Replies
3
Views
958
Replies
3
Views
1K
Replies
1
Views
1K
Replies
2
Views
1K
Replies
2
Views
615
Replies
2
Views
899
Top