All Questions
72
questions
2
votes
0
answers
32
views
Link between photon helicity and polarization of $A^\mu$ electromagnetic potential
From Wigner theorem we know that the irreducible unitary representation of the Poincarè group for massless and spin 1 particle is labelled by the momentum $p_\mu$ and the two possible helicity $+1,-1$ ...
- 613
2
votes
0
answers
97
views
How does a photon look like in QFT? [closed]
It is very well known that in QFT the particles are excitations of the field. But how exactly is a free photon looking like in spacetime? What is it shape in free space? And what is in fact in the ...
- 651
3
votes
2
answers
124
views
Are EM waves telling us the probability of finding a photon?
I feel like I've been frequently presented with an interpretation of EM waves that goes something like this:
Light is an oscillating electromagnetic field. Because changes in the electric field ...
- 203
5
votes
3
answers
1k
views
Why does light interact with normal matter but not with other light?
Why does light interact with normal matter but not with other light?
Assumptions:
Light does not interact with other light at all.
Light does interact with other matter, i.e reflection/refraction.
1
vote
3
answers
127
views
QED photon path (direction of photon emission)
In QED we look at all possible path a photon could go from S to P, and I understand the most significant contributions to the final arrow are the few near straight paths connecting S and P while other ...
- 161
25
votes
9
answers
6k
views
Why does light travel in a straight line if the uncertainty principle is true?
I've asked this on different websites and never gotten an answer that a layperson can understand. Most people just say that light does not have a trajectory and then they do some hand waving. If light ...
- 361
0
votes
0
answers
57
views
How to interpret light and photon?
I've been trying to solidify my understanding on properties of light and this is what my understanding is so far:
Light is an EM wave that travels in a constant speed C.
Light has a quantized energy ...
- 275
4
votes
3
answers
304
views
What makes a photon a photon?
As i understand photons are excitation of the electromagnetic field. Therefore charged particles are affected by this excitation. But what if we have (highly theoretically) a particle that has the ...
- 793
1
vote
0
answers
134
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Feynman's view about light
Professor Feynman, in his “QED: The strange theory of light and matter”, states at page 15:
“I want to emphasize that light comes in this form - particles. It is very important to know that light ...
- 53
0
votes
0
answers
102
views
Can Two Electromagnetic waves cancel each other if it 180 degree phase moving in same direction?
If we can send two electromagnetic waves -180 degree out of phase- in same direction, then the interaction of this wave with air molecules will be less due to the low intensity of the combination. So,...
- 81
1
vote
2
answers
186
views
How is electric field arising from photons? [duplicate]
This question has nothing in common with the question it is proposed to be duplicate e.g about virtual photons. The question is about a real radiation field where is known that no virtual photons ...
- 651
6
votes
2
answers
339
views
Where is a photon in space relative to the wave?
In electromagnetics you learn that an electromagnetic wave is a perturbation of the electric and magnetic fields that propagate in space according to the wave equation.
This makes sense when you are ...
- 161
2
votes
3
answers
424
views
Quantization of electromagnetic field [closed]
Every quantum optics book starts with quantization of electromagnetic field. Why?
My understanding:
The quantized electric field consist of photon and it helps to derive some properties of photon.
Is ...
- 123
6
votes
2
answers
2k
views
How to deduce existence of photons by applying quantum mechanics to Maxwell's equations
Watching this video lecture of Peter Higgs https://youtu.be/QtudlGHoBQ8?t=372, he says (roughly) at one point that Paul Dirac applied quantum mechanics to Maxwell's field equations and deduced the ...
- 193
2
votes
1
answer
93
views
Photon emmision from an accelerating particle
How does an accelerating charged particle emit a quantized photon?
Quantization of light makes sense to me if we were talking about vibrating charged particles or electron orbitals. But what about a ...
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