Real vs. Virtual Photons: A Comparison

In summary: However, in order to calculate the virtual fields, we use the mathematical approach first developed by Feynman. You won't see one, but they play an important role in the calculations.
  • #1
Ezio3.1415
159
1
What is the difference between real photons and virtual photons?
 
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  • #2
Real photons satisfy Einstein's energy relation (or: they are on-shell). Virtual photons don't. As a consequence, the first can be directly measured, the second cannot.
 
  • #3
Virtual photons are the force carriers of e.m. While real photons are little packets of energy... When two electrons repulse each other they do it because of the interaction of virtual photons... If they exchaned energy real photon would be emitted and absorbed... And in case of virtual photons no energy is exchanged... Did I get it?
 
  • #4
you have to be careful about the two repelling each other argument...

how would a proton and electron attract each other with that logic?
 
  • #5
Welcome to PF!

Hi Ezio3.1415! Welcome to PF! :smile:
Ezio3.1415 said:
What is the difference between real photons and virtual photons?

real photons are physics (they exist)

virtual photons are just maths (they don't)
Ezio3.1415 said:
When two electrons repulse each other they do it because of the interaction of virtual photons...

no, they do so because of the fields

the virtual photons in the maths help us to calculate the fields :wink:
 
  • #6
As tiny-tim explains, virtual photons appear in between the actual interactions, for the mathematical approach to QFT first used by Feynman. Normal photons enter into interactions (vertices of Feynman diagrams), and they can also emerge. As indicated by the name, you won't see one.
 
  • #7
Dipstick: I would say the same thing I guess... Interaction! :uhh:

Tim: Thank you... Hope to get a lot of help here... The forum's so active... :)

no, they do so because of the fields

the virtual photons in the maths help us to calculate the fields

But I thought standard model visualizes the field with the help of field particles,doesn't it? Or is it just the maths? But it makes total sense... It explains why the range of forces with virtual particles(the force carriers) so well...

Mark:
virtual photons appear in between the actual interactions, for the mathematical approach to QFT first used by Feynman. Normal photons enter into interactions (vertices of Feynman diagrams), and they can also emerge. As indicated by the name, you won't see one.
Can u explain that without Feynman diagram? :confused:
 

What is the difference between real and virtual photons?

Real photons are particles of light that can be observed and measured, whereas virtual photons are theoretical particles that are used to explain interactions between charged particles.

How do real and virtual photons behave differently?

Real photons travel at the speed of light and can be absorbed or emitted by particles, while virtual photons do not have a measurable speed and are only exchanged between particles during interactions.

Can real and virtual photons be distinguished in experiments?

No, real and virtual photons cannot be distinguished in experiments. Both types of photons have the same energy and properties, and their effects are indistinguishable.

How are real and virtual photons related to quantum electrodynamics?

Real and virtual photons are fundamental to the theory of quantum electrodynamics, which describes the interactions between charged particles and electromagnetic forces. Virtual photons are used to explain the exchange of energy and momentum between particles.

Are virtual photons just a theoretical concept or do they have real-world applications?

Virtual photons are primarily a theoretical concept used in quantum mechanics, but they have real-world applications in fields such as particle physics and quantum computing. Virtual photons play a crucial role in understanding the behavior of particles at the subatomic level.

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